Support jammr online jamming platform

These patches add support for http://jammr.net/, a new online jamming platform I am working on.

I am sending a separate email to the mailing list to describe the scope and vision behind jammr and how it will influence Wahjam.

jammr has features beyond what is available in the traditional protocol:

1. Private jams can be launched by users
2. Access control lists for private jams determine who is allowed to join
3. Permanent user accounts prevent spoofing other people's nicknames
4. All text is UTF-8 so that users with different language settings see the right characters

Some of these features are implemented by a REST API which is provided by the jamming platform.  Other features are implemented by an extended client <-> server protocol.

There are a few remaining patches in my personal repo which are not yet suitable for merging.  Over time they will be refactored and submitted too.  See https://github.com/stefanha/wahjam/commits/jammr.