fix: pkg: missing ~/.gitchangelog.rc and added some docs on how to install ``colour`` from git and from pip.
new: pkg: make sure that ``setup.py`` cannot be run without having run ``./autogen.sh``
new: pkg: is now pip git-installable. (fixes #5)

- ``gitchangelog`` is not required anymore to run ``setup.py``.
- ``gitchangelog`` failure should not prevent version to be edited.
- ``setup.py`` will run ``autogen.sh`` itself if needed.
new: pkg: setup travis.
new: colour is now compatible with python3.