Add a fast path for single render target masked clears in Renderer11.

TRAC #22898

Signed-off-by: Geoff Lang
Signed-off-by: Shannon Woods
Author: Jamie Madill

Conflicts:
	src/libGLESv2/libGLESv2.vcxproj.filters

git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@2219 736b8ea6-26fd-11df-bfd4-992fa37f6226
8 files changed