WinGui: x265 UI patch by Zhang Zhigiang. 

This enables support for the x265 encoder from the GUI when paired with a build of HandBrake that has x265 enabled. 
Thanks

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6062 b64f7644-9d1e-0410-96f1-a4d463321fa5