Editing documentation files from browser

[udono]

The following patch is a proof of concept which enables the editing of
rst-files from browser. (S.a. http://groups.google.com/group/sphinx-dev/browse_thread/thread/8041d64ed4ee7d2d
)
The official unofficial mime type is text/x-rst could bound to gvim or
another editor. (S.a. http://docutils.sourceforge.net/FAQ.html#what-s-the-official-mime-type-for-restructuredtext-data
)

+++ Instructions +++
After applying the patch, on the left column in the help system you
can find the link: Edit source.
On clicking it opens the original source (.rst) file for the page you
are viewing. You only need to bind the Mimetype for text/x-rst to your
favorite editor.


+++ Future ideas +++
Maybe for the 2. Release we can apply some helper functions which
provides an edit box inside the browser and a button to save/
(re-)build the new documentation.

Another point could be to create the documentation framework upon some
more functionalities with mercurial.
Buttons for hg pull/update and hg commit/push to an internet
repository.

But I think all this mercurial features are not so good for every
single user. Maybe we build an special buildername (see build.py) for
dev, like 'html-dev' which insert this functionality.

What do you think about?

[udono]

For the patch see:
https://bugs.tryton.org/roundup/issue457