Allow capitalized Admonition title.

If an adminition title is capitalized, the html class on the
div should still be lowercased.
Build_docs script now uses new Admonition extension.
Remove RSS Extension.

Closes #143. If you would like to continue using
the extension (not recomended), it is archived on
[Github](https://gist.github.com/waylan/4773365).
Preserve all blank lines in code blocks.

Fixes #183. Finally got this working properly. The key was
using a regex substitution with non-overlapping matches that
removed all whitespace from the begining of *all* blank lines
when normalizing whitespace.

Once I got that, I could simplfy the EmptyBlockProcessor
and easily output one or two blank lines appropriately.
A blank block gets two new lines (`'\n\n'`), while a
block which starts with a newline gets one.
Allow better linenum override in CodeHilite

Fixes #148. The "force_linenos" config setting of the CodeHilite extension has been
marked as Pending Deprecation and a new setting "linenums" has been added to
replace it. See documentation for the [CodeHilite Extension] for an explaination
of the new "linenums" setting. The new setting will honor the old "force_linenos"
if it is set, but it will raise a PendingDeprecationWarning and will likely be
removed in a future version of Python-Markdown.

[CodeHilite Extension]: extensions/codehilite.html
Make TocTreeprocessor extendable and be more gentle on badly structured headings
Merge pull request #191 from benjaoming/toc-fix

Make TocTreeprocessor extendable and be gentle on badly structured headings
code cleanup
Merge branch 'toc-fix'
Do not use assigned names "next" and "id", rename to order_toc_list and clean up code
adding test for out of order headlines
Merge pull request #192 from benjaoming/master

Little changes
Ensure toc attribute is available on Markdown class.

This appears to have recently been broken with the fixes in #191.
This time I've added tests to prevent future breakage and added
documentation to explain the behavior.
Updated toc extension to work with changes @ 4ff74e3.
TOC list item names must use text from all children.
More TOC cleanup and added tests.
Updated toc tests.
Various changes to docs for updated changes, clarity, and to fix typos.
Update docs/index.txt

Clarify that strict 4 space indentation applies to nested lists. 

Closes #193. Hopefully, people will read this in the docs before
filing bug reports in the future. One can dream.
Better clarify the 4 space indentation rule.

A better explanation for #193 that includes all block-level elements nested in lists.