Python.el recipes

This pull request updates the python.el recipe to pull the latest python.el from Emacs trunk. This should bring no issues because it is a goal to keep Emacs trunk's python.el compatible with Emacs 24.x.

It also adds a python24.rcp that points to the latest python.el contained in the emacs-24 branch, this particular version of python.el contains some minimal bugfixes and it's ensured to work with Emacs 24.x all the time.

The reason I'm updating this recipe is because I'm dropping the github repository for good, since it's been a pain to keep in sync since python.el is part of Emacs.