Restructure and refactor notification sending to be more cross platform
webhooks can be sent!
Add viewing of connected mobile devices to Account overview
Add UI for creating webhooks
Allow for deletion of webhooks
Allow pinging of a user's devices to make sure that it's up and responding
fix some little bugs with pinging android devices
Merge branch 'master' into webhooks

Conflicts:
	helpers/match_manipulator.py
Update documentation for webhooks
Don't allow insertion of duplicate webhooks
various semantic fixes
Move account registration check to a _require_registration method
remove debug logging statements
Bugfixes and other little things
Abstract notification building to base class
Move notification sending to its own class (to be used for testing later)
Simplify ndb queries for building dict of client IDs
Add test case for match score notification

Add tests for ping notification and update favorites

Tests for updated subscription notifcation

Add tests for base notification rendering
Support new indiana district. Fixes #1083
add event location to event list