OptionHandler for MAC addresses added.

For a project of mine I needed to parse MAC addresses. Mostly, MAC addresses are represented by a byte array of length 6 in Java. The string representation of a MAC address can be of different forms, e.g.

XXXXXXXXXXXX
XX XX XX XX XX XX
XX-XX-XX-XX-XX-XX
XX:XX:XX:XX:XX:XX

where X is a hexadecimal digit. I used an abstract delimiter (name it #) with the only constraint that # does not contain any hexadecimal digit. As an alternative, one can enter a string with 12 letters only containing hexadecimal digits.

You may want to merge my code to Your project. If You need more help (e.g. because I forgot something or made something wrong) please ask.