Initial implementation of release addres for maas
Merge branch 'environ-releaseaddress' into releaseaddress-maas
Test
Change ip to IP
Merge pull request #1181 from voidspace/releaseaddress-maas

Implementation of Environ.ReleaseAddress for maas

Implementation of maas provider. Release an ip address previously allocated with AllocateAddress.

(Review request: http://reviews.vapour.ws/r/492/)