grips-css: function to normalize selectors

[getify]

Whenever selectors are processed by the codegen, and they are base64 encoded for the grips partial id's, these selectors need to be normalized. Whenever render(..) is called with a selector, that selector should be normalized, so it can match when base64 encoded the proper grips partial.

Examples of necessary normalizations:

foo     bar

-> foo bar

foo     >       bar

-> foo > bar

foo    /* something */    bar

-> foo bar