Retool the access plugins to allow multiple plugins plus and/or switch. Retool selection criteria to use this allowing for a much richer selection of task handlers on a given page.

Checkpoint checkin: Can now create arbitrary pages! Yay. Task handler manipulation on arbitrary pages works, though there are some clear disconnects in the UI that will be addressed next. Not all page admin functions exist yet (no clone, enable, disable, revert, delete). Not all arguments have criteria yet.