Expand the admin interface

[jtanx]

UserCake has mostly just been reskinned to look like the rest of the GUI, so it comes with most of the standard options of UserCake. Some functionality may still be missing from the admin interface.

For example, it is quite difficult to select many users quickly for deletion. This may be accomplished using some JavaScript (jQuery) or through some other mass-deletion method.

The 'upload users' form should really be configured to generate random passwords that is emailed to each user, instead of setting one password that must be changed by the user.

It is also currently possible do delete yourself from the admin interface. This should be fixed.