Created GenerateMAC address goodie

a small goodie which generates a random MAC address when the user enters:
 * generate MAC at the beginning or end or,
 * random MAC at the beginning or end
added attribution
Stricter goodie triggers & formatting update
minor changes with queries and tests

including:
 * added a variety of new search options
 * proper html validation in tests added
 * return text in line with community standards
Merge pull request #262 from UnGround/master

Mac Address generator goodie