flesh out install a little
Update documentation and simplify README with pointer to full documentation on ReadTheDocs
Comment out static files gathering, as we are not using any custom static files
Simplify requirements.txt by just having the one that installs everything
needed by the developer (base requirements + testing tools +
documentation tools)

Add documentation building to the tox and travis test scripts.
Add note about shapely dependency.
Add more details to installation documentation about getting the development tools.
Fix minor typo in shapely dependency.
Fix docs badge in readme
Fix broken link in contributing doc page
Only run travis doc build on Python != 3.2