Allow EMObservation fields ra, dec, raWidth, and decWidth to be
blank in forms, resulting in a null database entry.

Modified events.view_utils.reverse to return an absolute url using
core.urls.build_absolute_uri.  This is helpful for when we issue
alerts without a request object available to construct the absolute
url.  Also updated the corresponding *toDict methods so as to
take advantage of this.

Changing from ISO format to another more readable format for
serialization functions in events/view_utils.py.  Changes for
things like EMObservations, EventLogs, etc.

Added a namespace to include() of superevents part of API. This fixes
an issue where reverse('api-root') was NOT returning the root of the
API but was rather returning /api/superevents/.

We added exception handling for certain create/destroy methods which
involve multiple object creation (log messages and/or tags) and which
may commonly raise errors, like tag creation with invalid characters.
This was done within the superevent viewsets and in the events api.

If a tag's name has some "uncommon" characters in it, like
parentheses (or probably others), it will cause errors for the
javascript which renders the event pages, since it tries to use
the tag name in the element id for the delete button.  We now require
that tags only use 0-9a-zA-Z_\- in their names. May have to go through
and delete some tags which use them.

Shortcuts modules were added for the events and superevents apps.
Currently, they just contain 'is_event()' and 'is_superevent()'
methods.

Instantiating a new alerts app and moving the alert functionality from
events/alert.py to alerts/old_alert.py. This commit forms a starting
point where the old alert functionality is still in place and we can
rework the alert infrastructure to be more modularized, flexible,
and adapted to superevents.

handle changes to writeLog client function and clean up display name handling for tagging of event logs

changing format for event EMObservations and EMFootprint creation timestamps when these objects are converted to dicts

Adding custom pagination to superevents API to match events. It's bad, but will have to serve until we can redo the whole thing

updating event tag and event log tag resources to include more information than just a link to the detail page

adding superevent API urls - currently nesting them within the events API; should eventually be moved to a separate API app

generalizing and abstracting several models in the events app, as well as fixing many field parameters

Need to make sure values are actually numeric types before
just passing them to isnan(), since it can't handle them, apparently.

Adding some requirements to migrations to enforce proper ordering.

Renaming LIB -> oLIB and gstlal-spiir -> spiir, at the request of
the pipelines.