Small build fix

Add files that were not added during the last commit

Patch from Samuel Cormier-Iijima <sciyoshi@gmail.com>:

IPv6 isn't completely working, I wasn't sure of the differences in the
is_mc_*'s. Also, ideally there should be a virtual
function in GInetAddress called g_inet_address_to_string that
delegates to either GInet4 or GInet6 to convert to a string
representation.

Pssst

Initial commit