Option to force a different address, return ERROR if required change failed

[nirgal]

Hello

Here are a couple of pacthes:

• --different option for paranoid distros
• don't return success if a change was requested and the address still is the same (double checking).

They are independant, you can take one or both if you like them.

Cheers

[erjoalgo]

It's not necessary to be paranoid to distrust macchanger's exit status, since it currently exits 0 (success) even if nothing at all was done due to wrong usage. So exit status doesn't have a clear meaning.

Also, that the mac did not change is no reason to exit as failure. For example, you might want to go back to the permanent mac, whether or not you're already there.