Merge pull request #392 from wpjunior/httpd_threading

Threading support for django httpd service
Initial changes to port lettuce to python 3.
requirements.txt contains the used dependencies.
After applying 2to3.py, several small changes were made.
Mox was replaced by Mock.
Still missing the django integration, apart from that, all the tests pass. (except the integration part)
fixing some unit and integrations tests.
port of the django integration to python 3
solved a problem with colorama on windows that affected some tests that had already been ported. cleaned lots of code.
removing old versions of django (the integration was ported using django 1.6.2)
integration tests passing for the 'alfaces' suite
added django 1.6.2 source to the lib dir of the of the integration tests
fixing typo on test name
integration tests passing for the suite 'bamboo'
added south to the settings.py so that django can see it
added pyYAML as a dependency
fixed an indentation at harvest.py
integration tests passing for the suite 'brocolis'
added south to the settings.py so that django can see it
integration tests passing for the suite 'celeries'
integration tests passing for the suite 'couves'
changes on the suite 'chive' (still not passing)
integration tests passing for the suite 'cucumber'
integration tests passing for the suite 'dill'
integration tests passing for the suite 'chive'
removing all the references to AdminMediaHandler (django 1.3) to StaticFilesHandler (django 1.6) as 1.6.2 is considered the base for this port.
Integration tests passing for the suite 'grocery'
Removed the setting LETTUCE_SERVE_ADMIN_MEDIA and it's behavior from the server.py. Django has changed a lot since version 1.3 that made it a little difficult to port. Removing it as I think the behavior can be added lately as needed. The test of this behavior har been removed from tests_grocery.py too.
Updated the urls of the admin media content on the tests.
Integration tests passing for the suite 'kale'
Integration tests passing for the suite 'rucola'
All tests passing!
Fixed a bug on the harvest command where it tried to process None objects. They are filtered now.
Fixed a bunch of typos.
Fixed a bug ontest_dill.py where it considered the order of the elements of a dict. That caused undefined behaviour. Ugly but effective to keep the same test.
Added coverage to requirements.txt
New RELEASE-NOTES.md and README.md
Merge remote-tracking branch 'origin/master'