Add test for stressing TypedArray garbage collection

Test that throw-away Float32Arrays used to update WebGL buffer data get
garbage collected reasonably instead of inflating the renderer memory
use.
Merge pull request #727 from NVIDIA/stress-test-array-buffers

Add test for stressing TypedArray garbage collection
Ternary Operators in Global Initializers

Add a test to verify that ternary operators can be used in global initializers.

Fragment shaders are of the form:
  precision mediump float;
  $(type) green = $(green);
  $(type) black = $(black);
  $(type) var = (true) ? green : black;
  void main() {
      gl_FragColor = $(asVec4);
  }

In order to pass, program should successfully link and output green.
Merge pull request #728 from RafaelCintron/ternaryOperatorsInGlobalInitializers

Ternary Operators in Global Initializers
Added conformance tests to check using WebGL canvases as texture sources.
Merge pull request #729 from toji/webgl_canvas_texture_source

Added conformance tests to check using WebGL canvases as texture sources