router: bridge `Connection: Upgrade` requests
router: bridge `Connection: Upgrade` requests

This is used for things like Websocket. The router should just treat
these as plain TCP connections and bridge the client to a backend.

Signed-off-by: Blake Gentry <f3924a1cf04dc10d9e836c6754e73f29db9a741d@gmail.com>

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