Use cgi.escape instead of markupsafe.escape

We don't declare a dependency to markupsafe, so we shouldn't use it, especially when cgi.escape is in the stdlib.
Remove unused mako option

grep -r escape adhocracy/templates   doesn't find a single invocation of this method. Furthermore, we don't actually depend on markupsafe, so this has always worked by accident.
Remove otudated workaround. We now depend on sqlite >=0.7.9
Depend on cssselect for testbrowser
moved PasteScript to normal dependencies to stop it from appearing in the adhocracy source code directory

Conflicts:
	setup.py
Fix norm/proposal assignment with relative_urls

Addendum to e74eaf6b0f0bda02dd3a69ac2e0065c6071c6503
Show category in proposal information box
indent
Allow assignment of categories to pages

It is now possible to assign categories to pages. The categories to be
assigned are the same categories as the proposal categories, as these
CategoryBadges are DelegateableBadges anyway, and can thus be used for
pages as well.

This way these categories may act as another bridge between proposals
and pages. If this isn't always desired, additional attributes can be
added later to the CategoryBadge model in order to define, whether a
category is meant as a proposal category, a badge category or both.

This commit doesn't add category facets to the page listing.
show category description in dropdown list instead of title
Merge branch 'develop' into geo
Use category color as page polygon background