tigefa4u projects Trac

Controller branch: migrated timeline module.

Controller branch: migrated attachment and about modules.

Further improvements to the attachment timeline events:
* do the usual wiki formatting on the description
* factor out common code from Wiki and Ticket timeline event providers;
put it in `AttachmentModule.get_timeline_events` helper method.

Controller branch: sync with [3444].

Remove the use of item access (`__getitem__`) for constructing HTML with the `Element`/`Fragment` classes, which has been found to be hard to read.

Ported session fix from Controller branch: ''loading'' an existing session was broken.

Controller sandbox: some simplification and fixes; migration settings controller.

Sandbox: initial changes for new controller branch.

Sandbox: restart controller branch.

Sandbox: restart controller branch.