router: add proxy.NewReverseProxy
router: add proxy.NewReverseProxy

Add the ReverseProxy constructor for initializing new sticky &
non-sticky reverse proxies.

Signed-off-by: Ben Burkert <73675debcd8a436be48ec22211dcf44fe0df0a64@benburkert.com>

shads196770/flynn,supermario/flynn,Brandywine2161/flynn,kgrz/flynn,ozum/flynn,josephglanville/flynn,jzila/flynn,TribeMedia/flynn,rikur/flynn,arekkas/flynn,jzila/flynn,benbjohnson/flynn,justintung/flynn,TribeMedia/flynn,rikur/flynn,technosophos/flynn,supermario/flynn,GrimDerp/flynn,josephglanville/flynn,tonicbupt/flynn,arekkas/flynn,supermario/flynn,whouses/flynn,technosophos/flynn,Brandywine2161/flynn,GrimDerp/flynn,benbjohnson/flynn,rikur/flynn,pkdevbox/flynn,ozum/flynn,whouses/flynn,arekkas/flynn,tonicbupt/flynn,schatt/flynn,kgrz/flynn,ozum/flynn,pkdevbox/flynn,clifff/flynn,flynn/flynn,supermario/flynn,technosophos/flynn,Brandywine2161/flynn,kgrz/flynn,felixrieseberg/flynn,schatt/flynn,whouses/flynn,arekkas/flynn,kgrz/flynn,pkdevbox/flynn,supermario/flynn,philiplb/flynn,felixrieseberg/flynn,TribeMedia/flynn,josephglanville/flynn,GrimDerp/flynn,lmars/flynn,Brandywine2161/flynn,whouses/flynn,justintung/flynn,TribeMedia/flynn,supermario/flynn,shads196770/flynn,lmars/flynn,benbjohnson/flynn,kgrz/flynn,ozum/flynn,philiplb/flynn,benbjohnson/flynn,justintung/flynn,lmars/flynn,felixrieseberg/flynn,benbjohnson/flynn,josephglanville/flynn,justintung/flynn,technosophos/flynn,jzila/flynn,philiplb/flynn,justintung/flynn,jzila/flynn,clifff/flynn,pkdevbox/flynn,schatt/flynn,technosophos/flynn,rikur/flynn,ozum/flynn,clifff/flynn,Brandywine2161/flynn,lmars/flynn,shads196770/flynn,lmars/flynn,josephglanville/flynn,schatt/flynn,kgrz/flynn,tonicbupt/flynn,whouses/flynn,shads196770/flynn,justintung/flynn,flynn/flynn,schatt/flynn,TribeMedia/flynn,ozum/flynn,TribeMedia/flynn,GrimDerp/flynn,felixrieseberg/flynn,GrimDerp/flynn,shads196770/flynn,rikur/flynn,pkdevbox/flynn,flynn/flynn,rikur/flynn,clifff/flynn,clifff/flynn,josephglanville/flynn,GrimDerp/flynn,benbjohnson/flynn,philiplb/flynn,tonicbupt/flynn,whouses/flynn,arekkas/flynn,Brandywine2161/flynn,flynn/flynn,clifff/flynn,tonicbupt/flynn,philiplb/flynn,jzila/flynn,jzila/flynn,schatt/flynn,shads196770/flynn,pkdevbox/flynn,flynn/flynn,felixrieseberg/flynn