Tidy up, removing debug prints, converting selected ones to watchdog logs
eltmc_googlesync.module - add a config form button which invokes the sync

For testing, and the impatient.

Some code tidying, testing and tweaking also done.
eltmc_googlesync.module - fix some bugs which manifest when actually updating google

And also add try/catch blocks around the google api calls to recover on
failure and prevent a single bad email to halt the entire update.
eltmc_googlesync.module - fix a type which causes group admins to be perpetually re-promoted

$group_admin used instead of $group_name means isOwner is always false.