WebSocket Support, Anonymous Authentication, new StropheJS, etc.

Big changes
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* StropheJS has been updated to the latest version which brings WebSocket support to cryptocat. I tested this with my own Server (prosody) and also with an ejabberd (+ node-xmpp-bosh as WebSocket Relay because WebSockets in ejabberd are only supported in the commercial version). I also did a lot of testing with the new StropheJS in general because I wrote the WebSocket implementation and I am also currently the maintainer of StropheJS…

* The register plugin has been dropped in favour of anonymous authentication. Cryptocat will no longer be able to create accounts and as a result there is no need for a cronjob that removes accounts any more. Any private cryptocat server will also have to enable anonymous authentication to work (This should not be a problem, all major servers support anonymous auth). Currently the crypto.cat server allows registration AND anonymous authentication. The registration on the server should be closed some time after merging this (when enough people updated cryptocat to this version).

Minor changes
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* Added a clean task to the Gruntfile that will remove all data that grunt creates in the build process
* Added a source-map file for jQuery for easier debugging
* fixed a bug that would reset on a connection object after the object was already deleted