Creating raw MBOX fixed (tests included)

Fix #278 and #271
For each group generate also a list of all mangled addresses.

Google Groups (rightly) protects addresses against spammers. There is
(obviously) no way how to find true value of these addresses
programmatically, so we just generate list of all affected ones, which
could be later completed with true values (collected somehow) and fixed
by some other script.

Fixes #275