tigefa4u projects Trac

Don't allow < characters in the target part of short links. Closes #804.

WebAdmin: use proper values for enabling/disabling components in [wiki:TracIni trac.ini].

WebAdmin: update to work with new `[components]` section for enabling/disabling components.

Note about `MacroList` not working when optimization is enabled. Closes #1044.

Site-wide wiki macros are no longer copied into each environment. Instead, the `UserMacroProvider` looks up macros in both the environment directory, and the global `wiki-macros` directory. This should fix the annoying and non-intuitive "Environment needs to be upgraded" message that would get raised when the macros were out of sync, and also fix #2140.

Map emails to login names in the bugzilla importer for owner changes. Closes #2120. Thanks as asmodai for the patch.

* Change the configuration for disabling components: instead of a `[disabled_components]` section that lists all components to be disabled, you can now enable/disable components in a `[components]` section. This also means that plugins need to be explicitly enabled for every environment. Closes #2019.
* Support a global `trac.ini` configuration file (by default in `$prefix/share/trac/conf`). Closes #1051. Thanks to Alec Thomas for the patch.

Load plugin eggs from `projenv/plugins` first.

Exclude description field from header in notifications.

Fix the fix in [2331]. Need. Unit. Tests. For. Notification. Code.