expose css selector definition on dojo.query

[Dustin Machi]

Right now it is not possible to implement custom css selectors (admittedly non standard). The code is hidden in dojo.query, exposing it would allow external code to modify and add these things as necessary while not sacrificing performance for those who don't.

[alex]

custom pseudo-selectors are exposed via dojo.query.pseudos. This is a map of pseudo-selector names to selector match functions, and this mapping can be extended. Exposing other query operators is not feasible since the burden of implementing the selector twice (once for xpath, once for DOM) seems too high.