Changed WebGL2 contextId to 'webgl2', removed version from WebGLContextAttributes
Add a test case to shader-with-short-circuiting-operators.html

To guard against incorrect unfold order.
This is the right one.
Merge pull request #397 from zhenyao/case

Add a test case to shader-with-short-circuiting-operators.html
Added test case from Bill Baxter (Google Maps team) for conditional discard optimization bug.
Merge pull request #398 from kenrussell/conditional-discard-bug

Added test case from Bill Baxter (Google Maps team) for conditional disc...
Added tests from Bill Baxter (Google Maps team) for floor() and mod() accuracy issues seen on some GPUs.
Merge pull request #399 from kenrussell/mod-div-bugs

Added tests from Bill Baxter (Google Maps team) for floor() and mod() ac...
Merge pull request #394 from toji/webgl2_contextid

Changed WebGL2 contextId to 'webgl2'
Add a shader with conditional side effects to the conditional discard bug
shader test.
Merge pull request #401 from jamiemadill/conditional-discard-side-effects

Test conditional discard with side effects