Support for Mail Lists and Contact Groups

I have finished adding support for synchronizing Thunderbird’s mail lists and Google’s contact groups in gContactSync.  It can do everything one would expect, such as reflecting changes in the contacts contained within groups, add/remove groups, etc. except if you rename a mail list or contact group the complementary group or mail list is not renamed (but still syncs fine).  UPDATE: It now detects if you have renamed a group or mail list and renames the other group/mail list.

I will hopefully finish testing and documenting the new code soon and release a new, improved test extension.  The ‘pencils down’ date is near (suggested date of August 11 to cleanup the code, deadline of the 18th).

Please let me know what you think about the existing test version so I can address any issues before the next release.  There are a few bugs I have since found and fixed.  One of the more serious bugs I found was contacts updated in Gmail after August began didn’t always update in Thunderbird, but, afaik, it has been fixed.