Fixed #141. Minor typo on wikilinks docs.

Thanks for the report.
setup.py: Add `long_description` attribute to `data`
so that there's no text breakage on PyPI page
Remove unneeded link
Merge pull request #142 from mitya57/master

Add `long_description` attribute to `data` in `setup.py`
Fixed #151. Raw html matching is now case-insensitive.
Fixed #152. Spaces in links are now escaped.
Fixed #153. Two spaces at end of paragraph is not a linebreak.
Apply a fix from commit 3e6e70eb48 to the bottom panel as well
Merge pull request #156 from mitya57/master

Fix the link in docs' bottom panel
Fixed #155. Early unescaping of inline placeholders now works when the placeholder is an Elementtree Element.
Fixed #154. Inline placeholders in img alt text are now unescaped.
A better fix for #155. Unescaping inline placholders now returns the text only of an Element - rather than the html which just gets html escaped in the output anyway.
Fix silly typo in previous commit.
Remove exec bit from extensions/fenced_code.py
docs/extensions/index.txt: make it clear what name to pass for extensions
docs/basic.css: Improve CSS a bit
Merge pull request #157 from mitya57/master

Improve docs/extensions/index.txt so that the name for each extension is properly identified.
Fixed minor typo in attr_list docs. 

Thanks @mitya57.
Fixed CodeHilite test when pygments is not installed.
Upped version to 2.2.1.