Gamma Support UserSync Endpoint (#2216)
Gamma Support UserSync Endpoint (#2216)

* commit gamma adapter

* Fixed The Travis CI build failed

* fix interpretResponse return empty when server response empty

* removed mediaType

removed mediaType in bid 
and return vastXml property if video request

* fixed Travis CI build

* Travis CI build

* add gamma spec

* fixed Travis CI build

* fix spec

* fix spec

* Add files via upload

* Add files via upload

* fix spec

* fix Travis CI build

* move to module

* remove gaxDomain param and move to adapter

* remove check isBidRequestValid for gaxDomain

* remove gaxDomain param

* remove gaxDomain param

* remove gaxDomain param

* Delete gammaBidAdapter_spec.js

* add usersync endpoid

* add usersync

indexexchange/Prebid.js,ImproveDigital/Prebid.js,guillaume-sticky/Prebid.js,nissSK/Prebid.js,Adikteev/Prebid.js,ImproveDigital/Prebid.js,Niksok/Prebid.js,nissSK/Prebid.js,polluxnetwork/Prebid.js,polluxnetwork/Prebid.js,olafbuitelaar/Prebid.js,mcallari/Prebid.js,PubWise/Prebid.js,tchibirev/Prebid.js,Adikteev/Prebid.js,Somoaudience/Prebid.js,prebid/Prebid.js,passit/Prebid.js,PubWise/Prebid.js,Niksok/Prebid.js,yieldbot/Prebid.js,HuddledMasses/Prebid.js,SpreeGorilla/Prebid.js,PWyrembak/Prebid.js,HuddledMasses/Prebid.js,prebid/Prebid.js,indexexchange/Prebid.js,HuddledMasses/Prebid.js,gumgum/Prebid.js,Somoaudience/Prebid.js,varashellov/Prebid.js,guillaume-sticky/Prebid.js,yieldbot/Prebid.js,PubWise/Prebid.js,varashellov/Prebid.js,gumgum/Prebid.js,ImproveDigital/Prebid.js,PWyrembak/Prebid.js,passit/Prebid.js,gumgum/Prebid.js,olafbuitelaar/Prebid.js,tchibirev/Prebid.js,mcallari/Prebid.js,SpreeGorilla/Prebid.js,Niksok/Prebid.js,PWyrembak/Prebid.js,prebid/Prebid.js