tigefa4u projects Trac

Fix for the `ExtensionOption` descriptor.

Integrated config fixes from #3037.

Follow-up to [3180], fix the About/configuration page.

Use logging for messages when writing sample config.

SpamFilter: some minor fixes.

SpamFilter: encode text as UTF-8 for Akismet requests.

Updates to SpamFilter plugin made necessary by [3180], and some fixes.

Fairly large change to the recently introduced `IConfigurable` mechanism that lets plugins declare options they support in [wiki:TracIni trac.ini].

Instead of using an extension point, the new mechanism uses descriptors (one of `Option`, `BoolOption`, `IntOption`, `ListOption`, or `ExtensionOption`) that can be added to any class (but especially `Component` subclasses), allowing direct access to the configured value. The `Option` class keeps a registry of all declared options, so that the defaults also work when the option is accessed through the `Configuration` object.

This also replaces the `SingleExtensionPoint` by the `ExtensionOption` descriptor.

Mimeview fixes, following-up to [3124].

The Mimeview.render should also handle `content` arguments which are objects with a `read` method. If the `mimetype` argument was not given, auto-detection would have failed.
Here, we take care to read the actual content, if needed, and at most once.

The logic about expanding tabs in the content has also been enhanced a bit,
so that not only the tab expansion is done at most once, but also the
expanded content is only given to the `IHTMLPreviewRenderer` who actually
requires an expanded content.

Don't show the TracBrowser ''View Changes'' when printing. Closes #3047.