Use "fix leaks" branches of rdbi, rdbi-driver-postgresql, m4dbi and libertree-model-rb .
Bump gems: rdbi-driver-postgresql, m4dbi, libertree-model-rb .
Bump libertree-model and, as a result, rdbi-driver-postgresql and pg.
Merge remote-tracking branch 'origin/master' into xmpp

Conflicts:
	Gemfile.lock