Migrates the Tool database to the new 1.7.10 format, that uses UUIDs 
instead of player names to designate players.
Migration runs in a separate thread, therefore its progress can only be 
watched from the server console.

The migration will run the following steps :
    - Checking if there are files to migrate. If not, the migration stops.
    - Checking if there are backups from a previous migration.
        If there are, the migration stops.
    - Retreiving the UUIDs of the players from Mojang's servers.
    - Checking if some UUIDs could not be retreived.
        This can happen if the player changed name before starting the 
        migration, of if using a non-paid account.
        If no UUID has been retreived at all, the migration stops.
    - Backing up name-based files and UUID-based files, to the Backup_Names and
        Backup_UUIDs subdirectories respectively.
        Backup's integrity are chacked using file size and SHA1 checksum.
        If integrity could not be proved, the migration stops.
    - Loading the old name-based tool stores to memory.
    §c--- From this step, changes to disk will be made, and you will have to use
    --- backups if you want to revert back from before the migration started.§r
    - Merging the old name-based tool stores with the new UUID-based ones, if
        there is any (which can be the case if your player started to use newer
        versions of CommandTools before the migration started).
    - Saving all these merged tool stores to disk.
    - Writing a list of all the migrated player's names, and their respective
        UUIDs, into a file named 'migratedusers.txt'.
    - Deleting the old name-based files from the main directory (they are still
        present in the apropriate backup directory just in case).

Note that this plugin will NEVER delete nor overwrite any backup directory.
Moving or deleting these backups is left to the administrator's responsibility.