- Added filter on load to help prevent potentially dangerous comment
HTML in DB at load time (if it gets passed input filtering, or is
existing).
- Added TinyMCE valid_elements for input wysiwygs, to gracefully degrade
content at point of user-view, rather than surprising the user by
stripping content, which TinyMCE would show, post-save.
- Updated mail notification design to be a bit prettier, and extracted
text to new lang file for translation.
- Added debounce logic for page update notifications.
- Fixed watch options not being filtered to current user.
Kept existing "COMMENTED_ON" activity for upgrade compatibility,
specifically for existing webhook usage and for showing comment
activities in activity lists.
Precursor to content notifications.
Currently untested.
Also applied some type updates.
