TRAC #11391
Checks for optional vertex declaration formats and falls back to FLOAT1-4 if more direct formats are not supporte

Signed-off-by: Nicolas Capens
Signed-off-by: Daniel Koch

Author:    Andrew Lewycky

git-svn-id: https://angleproject.googlecode.com/svn/trunk@330 736b8ea6-26fd-11df-bfd4-992fa37f6226