Enhancements on indentation code and related functions.
This commit includes:
* A more robust implementation of `python-indent-calculate-indentation'.
* enhancements on `python-indent-context' when dealing with backslashes
and blocks.
* Many changes, comments and enhancements to
`python-indent-calculate-indentation'. Many of them especially focused
to match pep8 guidelines, being this one the most important new one:
http://mail.python.org/pipermail/python-dev/2011-June/111760.html
* Better `python-info-line-ends-backslash-p' that would work as intended
on narrowed buffers.
* `python-info-continuation-line-p' now does what's supposed to do.
* Enhanced implementation of `python-info-continuation-line-p',
`python-info-block-continuation-line-p' and
`python-info-assignment-continuation-line-p'
New Functions:
* `python-util-forward-comment' a simple replacement `forward-comment'
with some necessary enhancements.