Don't include name of room for invites in push

Avoids insane pushes like, "Bob invited you to invite from Bob"

Add r0.2.0 to the "supported versions" list

Make the device id on e2e key upload optional

1. Add v2_alpha URL back in, since things seem to be using it.

2. Don't reject the request if the device_id in the upload request fails to
   match that in the access_token.

Clean up verify_json_objects_for_server

Conflicts:
	synapse/crypto/keyring.py

Add a couple more checks to the keyring

Fix a couple of bugs in the transaction and keyring code

We should now be able to get our device_id from the access_token, so the
device_id on the upload request is optional. Where it is supplied, we should
check that it matches.

For active access_tokens without an associated device_id, we ought to register
the device in the devices table.

Also update the table on upgrade so that all of the existing e2e keys are
associated with real devices.

Check if the user is banned when handling 3pid invites

Add `create_requester` function

Wrap the `Requester` constructor with a function which provides sensible
defaults, and use it throughout

Fix flake8 noise

Don't add rejections to the state_group, persist all rejections

Apparently flake8 v3 puts the error on a different line to v2. Easiest way to
make sure that happens is by putting the whole statement on one line :)

Apparently flake8 v3 doesn't like trailing comments on config settings.

Also remove the pep8 config, which didn't work (because it was missing W503)
and duplicated the flake8 config. We don't use pep8 on its own, so the config
was duplicative.

Implement updates and deletes for devices

Don't add rejected events if we've seen them befrore. Add some comments to explain what the code is doing mechanically