Clarify dissalowed WebGL comment

[jessegreenberg]

Part of #268. In BendingLightModel, the following line and comment exists:

    // if WebGL support then particles creation and propagation not need else we should create particles and propagate
    // to render them on canvas. Check to see if WebGL was prevented by a query parameter
    var disallowWebGL = phet.chipper.getQueryParameter( 'webgl' ) === 'false';

The code is clear, but the additional comment above this line is hard to understand. @samreid could you please clarify this documentation?

[samreid]

That comment was very confusing and unnecessary, I removed it in the above commit.

[jessegreenberg]

Sounds good, and looks good too. Thanks! Closing.