Investigate converting to using the AST tree entirely, or at least partially

[portante]

Using the AST tree might simplify the code (removing all kinds of pattern matching we do today on the CST tree) and allow additional features not possible with the CST tree.

It might also speed up the processing of source files (or not).

This is a place holder for tracking the pros and cons of making that switch. It should be noted that such a switch should have a significant enough benefit to out weigh any destabilization of the code in the mean time.

See also Issue #12.

[portante]

Might want to check out logilab-astng (http://www.logilab.org/856) for this as well.