Replace syutil dependency with smaller, single-purpose libraries

Remove autoincrement since we incrementing the ID in the storage layer

/tokenrefresh POST endpoint

Issue macaroons as opaque auth tokens

Conflicts:
	synapse/handlers/register.py

Correct pynacl version to 0.3.0

0.0.3 was a typo

Conflicts:
	synapse/rest/client/v1/login.py

This allows refresh tokens to be exchanged for (access_token,
refresh_token).

It also starts issuing them on login, though no clients currently
interpret them.

Clean up some of restructured text formatting in the README.rst

Add generic update instructions to UPGRADE.rst

Add m.room.avatar to default power levels.

We're about to have two kinds of token, access and refresh

Fix set password

Add m.room.avatar to default power levels. Change default required power levels of such events to 50