Flip urlize and linebreaks conversion for plain rendering for cleaner rendering

Django's urlize is somewhat wired: e.g 'Foo http://bar.com' will result in
'<p>Foo <a href="http://bar.com%3C/p%3E">http://bar.com</p></a>' for
urlize(linebreaks(escape(text))). Flipping `urlize` and `linebreaks`
results in the expected output with clean line breaks / paragraphs:
'<p>Foo <a href="http://bar.com">http://bar.com</a></p>'
Merge pull request #14 from Markush2010/fix/plain-markup-rendering

Flip urlize and linebreaks conversion for plain rendering for cleaner rendering