tigefa4u projects Trac

Remove unneeded compatibility code from the `trac.web.href` doctest runner.

Testing: remember to print the skip message.

Testing: Handle missing subprocess; better handling of server startup.

* Switch back to the `sys._getframe()` hack in the implementation of `implements()`, for better thread-safety and nesting support (see [http://groups.google.com/group/trac-dev/browse_thread/thread/7bccf999eb3407ed mailing list post]). Also, made `implements` a static method on the `Component` class, which is then aliased to a module-level function.
* Cleaned up imports in `trac.config`, and use `fileobj.write()` instead of `print>>fileobj` when serializing the configuration.

Testing: remove unused PIPE

Testing: use compat for 2.3

Make the nav item to the current admin page an actual link, to accomodate the need to "jump back up" on "deeper" admin pages.

Remove debug logging leftover from r5912.

Tweak fix for #5819, cached changesets being returned in the opposite order if they happen in the same second

Testing: doc fix