This is to work around driver bugs.  We added more functions, and removed some unnecessary ones.  Remove the function group because we have flags for each function now.  Use more macros instead of functions.  Don't emit global precision because that will affect all later code.

ANGLEBUG=196
TEST=build and test on Mac ATI/NVIDIA, fixes the failing webgl glsl conformance tests.
Review URL: http://codereview.appspot.com/5011053

git-svn-id: https://angleproject.googlecode.com/svn/trunk@754 736b8ea6-26fd-11df-bfd4-992fa37f6226