Bump libx265 to version 0.8.

Miscellaneous fixes and improvements, and simplify
the patch to fix multiple inclusions of x265.h


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6114 b64f7644-9d1e-0410-96f1-a4d463321fa5
QSV: fix preset names for Ivy Bridge and earlier.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6115 b64f7644-9d1e-0410-96f1-a4d463321fa5
libhb: fix fps calculation when number of previews is very small


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6116 b64f7644-9d1e-0410-96f1-a4d463321fa5
WinGui: Fix an issue with the preview scan count not being set correctly for libhb encode path.
Added Nightly appcast update checking functionality back in.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6117 b64f7644-9d1e-0410-96f1-a4d463321fa5