Restructure bundles, so that we add bundles to items and rooms explicitly, rather than setting a bundle field on the item assignments. This has meant quite a few changes elsewhere. We now have BundleRoomAssignments and BundleItemAssignments. All of this is so that we can delete bundles from items and rooms directly. At time of writing, there are still six failures in tests.py to resolve, but no errors.
Also removed a few blocks of commented-out template code, where the majority of content had been replaced by tables.
Corrected the remaining errors after switching to the different bundle implementation. Now all tests pass again.
Making some corrections to the Help pages - fixing out-of-date stuff, correcting typos, etc.