whitespace cleanup

[Andrea Crotti]

So apparently PythonTidy uses the AST (the compiler module) to find out 
the problems,
and generates new nodes with a put method to write out the code with the 
fix.

An awful lot of code is needed to make it work apparently, not very neat.
Pep8 instead uses tokenize and regular expressions only, and the code
is much neater, not sure how is possible to make it fix things though.