Mention 'go get' command in the README file.
Mention 'go get' command in the README file.

This is necessary to build webtry.go as it imports packages from
github.com

BUG=None
TEST=follow the README instructions
R=humper@google.com, jcgregorio@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/601033004

MarshedOut/android_external_skia,chenlian2015/skia_from_google,nfxosp/platform_external_skia,pcwalton/skia,OneRom/external_skia,MinimalOS-AOSP/platform_external_skia,todotodoo/skia,chenlian2015/skia_from_google,Jichao/skia,nvoron23/skia,w3nd1go/android_external_skia,noselhq/skia,noselhq/skia,boulzordev/android_external_skia,google/skia,google/skia,nfxosp/platform_external_skia,nfxosp/platform_external_skia,geekboxzone/mmallow_external_skia,Igalia/skia,AOSP-YU/platform_external_skia,invisiblek/android_external_skia,HalCanary/skia-hc,rubenvb/skia,noselhq/skia,ominux/skia,samuelig/skia,geekboxzone/mmallow_external_skia,w3nd1go/android_external_skia,vanish87/skia,BrokenROM/external_skia,Igalia/skia,aosp-mirror/platform_external_skia,nvoron23/skia,noselhq/skia,BrokenROM/external_skia,VRToxin-AOSP/android_external_skia,noselhq/skia,timduru/platform-external-skia,tmpvar/skia.cc,boulzordev/android_external_skia,timduru/platform-external-skia,YUPlayGodDev/platform_external_skia,AOSP-YU/platform_external_skia,tmpvar/skia.cc,AOSP-YU/platform_external_skia,spezi77/android_external_skia,PAC-ROM/android_external_skia,spezi77/android_external_skia,TeamTwisted/external_skia,w3nd1go/android_external_skia,MarshedOut/android_external_skia,OneRom/external_skia,tmpvar/skia.cc,TeamExodus/external_skia,shahrzadmn/skia,invisiblek/android_external_skia,tmpvar/skia.cc,ominux/skia,amyvmiwei/skia,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,scroggo/skia,amyvmiwei/skia,scroggo/skia,qrealka/skia-hc,nvoron23/skia,invisiblek/android_external_skia,VRToxin-AOSP/android_external_skia,MinimalOS-AOSP/platform_external_skia,nvoron23/skia,HalCanary/skia-hc,AOSPB/external_skia,samuelig/skia,AOSP-YU/platform_external_skia,geekboxzone/mmallow_external_skia,amyvmiwei/skia,ominux/skia,noselhq/skia,pcwalton/skia,UBERMALLOW/external_skia,OneRom/external_skia,Jichao/skia,w3nd1go/android_external_skia,invisiblek/android_external_skia,UBERMALLOW/external_skia,TeamTwisted/external_skia,google/skia,samuelig/skia,aosp-mirror/platform_external_skia,BrokenROM/external_skia,samuelig/skia,rubenvb/skia,DiamondLovesYou/skia-sys,AOSPB/external_skia,todotodoo/skia,TeamExodus/external_skia,nvoron23/skia,nfxosp/platform_external_skia,MarshedOut/android_external_skia,TeamExodus/external_skia,geekboxzone/mmallow_external_skia,shahrzadmn/skia,DiamondLovesYou/skia-sys,MonkeyZZZZ/platform_external_skia,PAC-ROM/android_external_skia,jtg-gg/skia,YUPlayGodDev/platform_external_skia,rubenvb/skia,chenlian2015/skia_from_google,HalCanary/skia-hc,MonkeyZZZZ/platform_external_skia,TeamExodus/external_skia,shahrzadmn/skia,nfxosp/platform_external_skia,todotodoo/skia,boulzordev/android_external_skia,shahrzadmn/skia,boulzordev/android_external_skia,tmpvar/skia.cc,TeamTwisted/external_skia,YUPlayGodDev/platform_external_skia,VRToxin-AOSP/android_external_skia,PAC-ROM/android_external_skia,todotodoo/skia,nfxosp/platform_external_skia,UBERMALLOW/external_skia,pcwalton/skia,google/skia,todotodoo/skia,w3nd1go/android_external_skia,YUPlayGodDev/platform_external_skia,BrokenROM/external_skia,MonkeyZZZZ/platform_external_skia,tmpvar/skia.cc,chenlian2015/skia_from_google,Hikari-no-Tenshi/android_external_skia,w3nd1go/android_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,google/skia,TeamTwisted/external_skia,AOSPB/external_skia,geekboxzone/mmallow_external_skia,Hikari-no-Tenshi/android_external_skia,AOSP-YU/platform_external_skia,jtg-gg/skia,ominux/skia,PAC-ROM/android_external_skia,google/skia,geekboxzone/mmallow_external_skia,shahrzadmn/skia,OneRom/external_skia,timduru/platform-external-skia,VRToxin-AOSP/android_external_skia,VRToxin-AOSP/android_external_skia,AOSP-YU/platform_external_skia,Igalia/skia,BrokenROM/external_skia,YUPlayGodDev/platform_external_skia,amyvmiwei/skia,HalCanary/skia-hc,rubenvb/skia,samuelig/skia,Infinitive-OS/platform_external_skia,vanish87/skia,Igalia/skia,TeamTwisted/external_skia,BrokenROM/external_skia,VRToxin-AOSP/android_external_skia,MinimalOS-AOSP/platform_external_skia,nvoron23/skia,TeamExodus/external_skia,YUPlayGodDev/platform_external_skia,ominux/skia,AOSPB/external_skia,OneRom/external_skia,amyvmiwei/skia,spezi77/android_external_skia,nfxosp/platform_external_skia,tmpvar/skia.cc,noselhq/skia,AOSP-YU/platform_external_skia,w3nd1go/android_external_skia,VRToxin-AOSP/android_external_skia,rubenvb/skia,UBERMALLOW/external_skia,nfxosp/platform_external_skia,google/skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,UBERMALLOW/external_skia,PAC-ROM/android_external_skia,aosp-mirror/platform_external_skia,geekboxzone/mmallow_external_skia,pcwalton/skia,boulzordev/android_external_skia,scroggo/skia,MarshedOut/android_external_skia,Jichao/skia,invisiblek/android_external_skia,MonkeyZZZZ/platform_external_skia,amyvmiwei/skia,DiamondLovesYou/skia-sys,scroggo/skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,vanish87/skia,MinimalOS-AOSP/platform_external_skia,chenlian2015/skia_from_google,UBERMALLOW/external_skia,YUPlayGodDev/platform_external_skia,ominux/skia,Jichao/skia,PAC-ROM/android_external_skia,aosp-mirror/platform_external_skia,shahrzadmn/skia,TeamExodus/external_skia,Infinitive-OS/platform_external_skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,MonkeyZZZZ/platform_external_skia,OneRom/external_skia,Jichao/skia,google/skia,samuelig/skia,VRToxin-AOSP/android_external_skia,MarshedOut/android_external_skia,qrealka/skia-hc,TeamTwisted/external_skia,MinimalOS-AOSP/platform_external_skia,invisiblek/android_external_skia,jtg-gg/skia,MonkeyZZZZ/platform_external_skia,Jichao/skia,w3nd1go/android_external_skia,samuelig/skia,Jichao/skia,DiamondLovesYou/skia-sys,samuelig/skia,pcwalton/skia,geekboxzone/mmallow_external_skia,Infinitive-OS/platform_external_skia,Jichao/skia,pcwalton/skia,OneRom/external_skia,tmpvar/skia.cc,todotodoo/skia,MarshedOut/android_external_skia,Jichao/skia,nvoron23/skia,Infinitive-OS/platform_external_skia,MinimalOS-AOSP/platform_external_skia,AOSP-YU/platform_external_skia,rubenvb/skia,HalCanary/skia-hc,BrokenROM/external_skia,AOSPB/external_skia,OneRom/external_skia,timduru/platform-external-skia,vanish87/skia,jtg-gg/skia,Infinitive-OS/platform_external_skia,qrealka/skia-hc,YUPlayGodDev/platform_external_skia,rubenvb/skia,scroggo/skia,PAC-ROM/android_external_skia,pcwalton/skia,amyvmiwei/skia,invisiblek/android_external_skia,MarshedOut/android_external_skia,amyvmiwei/skia,rubenvb/skia,UBERMALLOW/external_skia,pcwalton/skia,spezi77/android_external_skia,shahrzadmn/skia,nvoron23/skia,Igalia/skia,PAC-ROM/android_external_skia,qrealka/skia-hc,Infinitive-OS/platform_external_skia,TeamExodus/external_skia,Igalia/skia,MonkeyZZZZ/platform_external_skia,Igalia/skia,todotodoo/skia,PAC-ROM/android_external_skia,TeamTwisted/external_skia,ominux/skia,timduru/platform-external-skia,VRToxin-AOSP/android_external_skia,YUPlayGodDev/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,pcwalton/skia,noselhq/skia,qrealka/skia-hc,vanish87/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,todotodoo/skia,chenlian2015/skia_from_google,Hikari-no-Tenshi/android_external_skia,TeamExodus/external_skia,AOSP-YU/platform_external_skia,vanish87/skia,MonkeyZZZZ/platform_external_skia,shahrzadmn/skia,aosp-mirror/platform_external_skia,nvoron23/skia,chenlian2015/skia_from_google,spezi77/android_external_skia,todotodoo/skia,MinimalOS-AOSP/platform_external_skia,geekboxzone/mmallow_external_skia,tmpvar/skia.cc,aosp-mirror/platform_external_skia,shahrzadmn/skia,MinimalOS-AOSP/platform_external_skia,vanish87/skia,Hikari-no-Tenshi/android_external_skia,TeamTwisted/external_skia,nfxosp/platform_external_skia,jtg-gg/skia,TeamTwisted/external_skia,AOSPB/external_skia,rubenvb/skia,ominux/skia,jtg-gg/skia,scroggo/skia,OneRom/external_skia,AOSPB/external_skia,timduru/platform-external-skia,UBERMALLOW/external_skia,MinimalOS-AOSP/platform_external_skia,timduru/platform-external-skia,HalCanary/skia-hc,scroggo/skia,jtg-gg/skia,scroggo/skia,Igalia/skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,DiamondLovesYou/skia-sys,ominux/skia,noselhq/skia,AOSPB/external_skia,vanish87/skia,google/skia,aosp-mirror/platform_external_skia,TeamExodus/external_skia,invisiblek/android_external_skia,aosp-mirror/platform_external_skia,vanish87/skia,HalCanary/skia-hc,qrealka/skia-hc,w3nd1go/android_external_skia,AOSPB/external_skia,DiamondLovesYou/skia-sys,BrokenROM/external_skia,google/skia,UBERMALLOW/external_skia,MarshedOut/android_external_skia,qrealka/skia-hc,spezi77/android_external_skia,MonkeyZZZZ/platform_external_skia,DiamondLovesYou/skia-sys,boulzordev/android_external_skia,Hikari-no-Tenshi/android_external_skia,MarshedOut/android_external_skia