Fix ambiguous reference dictation module docs

The reference to the DictationContainerBase.format() method from the
module-level docstring was ambiguous, so I made it absolute to remove
the ambiguity. I also changed the reference to the
DictationContainerBase.words property to be of the attr role instead
of the previous meth role.
Move license from subdir to root

I moved the dragonfly/license.txt file to LICENSE.txt in the package
root, to be consistent with the standard package layout described here:
http://guide.python-distribute.org/creation.html
Update URL and license details in setup.py

I changed the URL specified in setup.py from Google Code to GitHub.
I changed the license parameter to reference the LICENSE.txt file and
broke the license classifier line to fit within 80 characters.
Add empty AUTHORS.txt and CHANGES.txt files

I added these files to be in line with the standard package layout as
described here: http://guide.python-distribute.org/creation.html
Expand description of release process
Expand description of release process