Direct Beaker integration

[Christopher Allan Webber]

We should bundle Beaker directly into GNU MediaGoblin. Right now it's set up as middleware in server.ini, but this isn't ideal for the following reasons:

• Beaker is in no way optional middleware. It's absolutely essential for launching the application.
• Things like ./bin/gmg shell don't give you a fully functioning application because they just read mediagoblin.ini which doesn't contain information on how to set up Beaker, so it is never set up
• We need to have a paste config in order to launch tests
• Complicates writing scripts that interface with mediagoblin So here's a solution.
• Create a ['beaker'] section in mediagoblin.ini and mediagoblin/config_spec.ini
• Add a utility to create the beaker instance based on the ['beaker'] section of the config
• Use that utility in MediaGoblinApp.**init**() and push it into mg_globals