Decorator

Included a patch from Zev Benjamin: now decorated functions play well
with cProfile.

Added a warning about the memoize example, as requested by Robert
Buchholz.

docs/README.rst was not included in MANIFEST.in by accident,
thus breaking the source installation.

Added docs directory and upload_docs command. Fixed bug with
`__qualname__`, reported by Lucian Petrut.

Removed the need for 2to3 by dropping the support for Python 2.5.
Added a MANIFEST.in file and produced a proper wheel. Improved
the integration with setuptools so that `python setup.py test` works.
Reworked the documentation and introduced `decorator.decorated`.
Removed any dependence from `inspect.getargspec`, which is deprecated
in Python 3.5, as signaled by Ralf Gommers.
Fixed `contextmanager` to work with Python 3.5.
Copied the `__qualname__` attribute, as requested by Frazer McLean.
Added a `dispatch_on` facility to implement generic functions.

Same as 3.4.1, re-uploaded to PyPI.