Support the new static bundles for extensions.
This updates to support the new static bundles for extensions. The

appropriate template tags have been placed in the base template, so that

the default bundles will be loaded.
There's also a new reviewboard.extensions.packaging module, which

contains a setup function that an extension's setup.py can use in place

of the standard setuptools one. This will set some required options for

the package, and set things up to install static bundles.
The documentation and extension generator have been updated.

Built an extension and verified that the bundles were generated and packaged.
Tested with a local extension in a development server setup and a production

setup, and with the extension in a 'setup.py develop' mode and installed.
Read through the user manual.