Provide a documentation package

It would be nice to provide a python-quickly.widgets-doc package containing the API documentation generated from the existing docstring packages.

Sphinx [1] seems to be the tool generally used to build nice Python documentation.

A few pointers for anyone wanting to take up this task:

* An example to look at is the python-apt-doc package, which generates these docs [2].
* I believe the main changes are to add the 'build_sphinx' command to setup.py:
http://bazaar.launchpad.net/~mvo/python-apt/debian-sid-mirrored/view/head:/setup.py#L20
* Then call it from debian/rules, and add the doc/ folder with a Makefile for Sphinx.
* The python-quickly.widgets should build an additional python-quickly.widgets-doc binary package containing the documentation

[1] http://sphinx.pocoo.org/
[2] http://apt.alioth.debian.org/python-apt-doc/