tigefa4u projects Trac

Fix for being able to load eggs produced by setuptools-0.6 on windows.

vc-refactoring: minor improvements to the TracBrowser
* Decided that the jump to a branch or tag feature is useful anywhere
in the TracBrowser, not just from the root.
* Improve the stylesheet for displaying the revision numbers
(we need fixed character width)
* Better default size for the ''View Revision'' field
(should that be made configurable, and how?)

vc-refactoring: Refactored changeset event provider logic in Repository.get_changesets method

This is useful for two reasons:
* that specific algorithm works for the SVN backend in generic terms,
so the implementation can be pushed as the generic default
* for SCM where this algorithm doesn't work, it's easily overridable
and the web_ui is left unchanged

vc-refactoring: Shortened old/new revision names in diff listing

Nothing changed for Subversion, but quite helpful for SCM having
long changeset identifiers...

vc-refactoring: Add the possibility to select branches and tags from the browser interface.

vc-refactoring: Add the possibility to show additional changeset properties.

vc-refactoring: The versioncontrol.web_ui modules are now abstract components.

This makes it possible to slightly change their behavior in derived classes
for supporting other SCM backends.

'''Note: this is most probably a temporary situation, if the coming up changes
are propagated to the generic classes, there will be no need for that.'''

Also, the ''Next Changeset'' link is sometimes not existing, even if
the changeset currently shown is not the last one (i.e. end of branch situation).

vc-refactoring: `IScmBackendInterface` and `ScmBackendManager` introduced.

This is similar to what I did for the source:branches/cboos-dev/db-refactoring
so there will be some opportunity for code sharing.

Now there is support for creating a Trac environment without specifying a repository
(see #156).

Also, by specifying the prefix 'direct-svn-fs', one can use the Subversion backend
without the cache, which can be useful for development or if you're annoyed by the
'resync' command...

vc-refactoring: Changeset next/prev navigation links are always both present.

Simply, the next or prev link is inoperant and dimmed out if there's no such changeset.

vc-refactoring: Refactored the revision navigation
* don't cache all existing revisions in the case of a scoped repository
* next_rev and prev_rev use the history, even in the case of a non-scoped
repository, as this does authorization checks
* oldest_rev should be 1, not 0