additional check to make sure that vertexAttribPointer isn't called for not active attribute (case when getAttribLocation returns -1)
Add a 1 channel jpg texture test.

This passes on Chrome and Firefox but generates an incorrect
`INVALID_VALUE` error on Safari
Merge pull request #451 from imzet/utils-vbo-use

additional check to make sure that vertexAttribPointer isn't called for ...
Merge pull request #457 from greggman/add-1-channel-jpg

Add a 1 channel jpg texture test.
Fix up WEBGL_debug_shaders test.

getTranslatedShaderSource() should return "" instead of null on failure.
Fixed JS error where newTranslatedSource was not forward-declared.
Merge pull request #458 from jdashg/debug_shaders

Fix up WEBGL_debug_shaders test.