Fixed uniform and attribute parsing

The current parser for uniforms and attributes does not accept multiple declaration as in:

attribute float a,b;
uniform float a, b;

Also, I added a removed comments function for case like:

// attribute float a;

were parsed  and the attribute was created.


What I meant to ask was, is it a duplicate of the code below in `attributes` section? If it is (or is even close, which it appears to be), we should unify/functionalize it.