Added errors notification category.
Added dates to notifications.
Added default metadata schemas to intializedb.py
Initial implementation of dataset calibrations (untested).
Updated test processing script (ArtificialTreeProcessing.py)

Refactor of locking for improved performance (previous AJAX method onunload caused noticable navigation delays) - New functionality is implemented in view.__init__ and AJAX unlocking is only run when required.  There is still an issue where non-form pages will never unlock, which leaves extra data in DB until they expire.
Merge branch 'master' of https://github.com/jcu-eresearch/TDH-rich-data-capture