tigefa4u projects Trac

TracDiff: a few fixes
* the optimized list of diff entries simply
ignored the added and deleted files in addition
to the files with no real differences. Fixed.
* removed the ''Zip Archive'' link when browsing the root:
it didn't work and it was anyway not a good idea to
download the whole repository...
* correctly track directory ADDs

TracDiff: refactored the Diff._render_html method to do everything in one pass.

Previously, the nodes where stored and this would cause a
''Too many files opened'' system error for big differences
(each node consumes a file, at least with the FSFS backend).

TracDiff: simplified the interface and the code
* Interface Changes
* The Log view only offers ''Diff between revisions of a path''
* The Browser view is the one to use for ''Arbitrary diffs''
* As an added bonus, the Browser now offers the possibility to
download a zip file containing everything below the directory
being browsed (at the current revision). This would solve #238.
* API Changes
* the Repository.get_diffs method is now supposed to simply yield
{{{(old_node, new_node, kind, change)}}} tuples
* In the Diff view, I hopefully got right the usage of (path,rev) vs.
(created_path, created_rev): the former information is used
for creating hrefs for Trac, and the created_rev information
is simply displayed. This is similar to what the Browser does.

What's remaining:
* there's the ''View previous diff'' stuff to fix
* I'll try to refactor the Diff.py and the Changeset.py
in order to share more code

make Wiki formatter keep proper XHTML ordering of closing tags (fixes #1634)

add missing __future__ import for generators

oops, fixing a stupid error in [1770]

Small fixes for TracDiff (reverting to a simpler title for the Diff module, fix the diff for single files, CSS fixes for IE...)

Add back 'update' key to fix changing diff options in wiki. Closes #1643.

Fix changing the diff options in the wiki diff view. Closes #1611.

TracDiff interface enhancements:
* less intrusive ''Diff'' panel in the Browser and the Log view
* the panel is not shown when browsing the ''root''
* more consistent specifications of path/revs
(don't try to use the created_path/created_rev information)
* Improved the display of the title for the Diff module
* added a ''Reverse Diff'' link in the Diff module,
to invert the '''from''' and '''to''' parameters
* while showing the diffs entries, show the created revision information
for the old and new files, not the global ''old'' and ''new'' revisions.
This is especially useful while diffing between branches,
so that one can see which side is the most recent on a file per file basis.