Bump entity version, add entity-subscription requirement.
Fixed entity upgrade breaking changes.
Integrate entity_subscription. Re-write tasks.get_email_addresses.
Tests passing.
Test custom email settings.
Upgrade entity_subscription, improve send_to filtering.
Revised readme for new subscription model.
Added get_medium utility function.
Import ordering.
add_email_medium management command and tests.
Added optional `from` field to email object.
Added initial migrations.
Bump minor version number.
flake8 cleanup
Converted readme to reStructuredText
Setup.py points to the correct readme file.
Project description and other setup.py stuff.
Merge pull request #6 from Wilduck/remove-subscriptions

Replace custom subscription with entity-subscription