Fill all the gaps

If you are using the auto-numbering in MacNamer, it will now fill up the gaps in the numbering. If you have 1, 2, 4 and 5 used, it will issue number 3 when the next machine requests a new name. This is useful when you've deleted old machines and want to re-use it's number.

The client script will now correctly re-name the machine if the number of leading zeroes changes.