2to3 refactoring

Moves cmdline processing logic out of RefactoringTool and into its own module lib2to3.main. See issue #3637.

[gregory.p.smith, 2008-09-02 05:46:23]

http://codereview.appspot.com/3247/diff/1/3
File lib2to3/tests/support.py (right):

http://codereview.appspot.com/3247/diff/1/3#newcode42
Line 42: def get_refactorer(fixers=None, options={}):
using {} as a default arg is dangerous.  in this case you just pass it to
RefactoringTool which as its currently written copies things out of it rather
than keeping a reference and modifying it.  But that could change.  Please
change the default to None and add a docstring mentioning that it should be a
dictionary.

[Benjamin, 2008-09-02 22:19:46]

take Greg's advice (thanks!)