Trac #12909

Implements GL_OES_texture_float, GL_OES_texture_half_float,
GL_OES_texture_float_linear, and GL_OES_texture_half_float_linear
when supported by the hardware.

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

Author:    Shannon Woods <shannon.woods@transgaming.com>

git-svn-id: https://angleproject.googlecode.com/svn/trunk@404 736b8ea6-26fd-11df-bfd4-992fa37f6226