[Firehol-support] Allow Acces by Mac address not ip?

[Costa Tsaousis]

Hi,

There was some mac support as an optional rule parameter since v1.134, but
surprisingly enough... I forgot to document it!

After re-examination I found it was faulty too. So, I added full (I hope)
support for the mac optional rule parameter now, in the CVS version 1.179
and updated the CVS documentation to reflect the change.