updating query and forms to remove module-level database queries; some resulting changes to view logic for handling labels were also required

Django 1.11.5 upgrade

See merge request !5

re-organizing events requiring operator signoff on home page into groups of 'submitted within the last 24 hours' and 'older than that'

fixing middleware account creation - creates User objects rather than LigoLdapUser, then overnight LDAP cron job will create LigoLdapUser for LIGO accounts

fixing display for Trigger and Contact models as this caused errors in IPython with certain unicode characters

Adding offline boolean parameter to Event model class

See merge request !4

adding offline boolean parameter to Event model class and associated code for handling it during event submissions

Allow events to be created with labels

See merge request !3