* Split BackupPC_Admin into a set of modules, one for each major action.

* Split BackupPC_Admin into a set of modules, one for each major action.
  Each action is now a seperate module in lib/BackupPC/CGI.

* Added directory history display to BackupPC_Admin, allowing the
  user to quickly see which files changed between backups.

* Swapped the Server and Hosts sections on the Nav bar.  Moved the
  host search text box to the top of the hosts section.  This was
  done to move the variable-length part of the Nav bar (when all
  hosts are displayed) to the bottom.