merge from marius
Patches applied:

 * marius.gedminas@canonical.com/launchpad--calendars--0--base-0
   tag of james.henstridge@canonical.com--2004/launchpad--devel--0--patch-1

 * marius.gedminas@canonical.com/launchpad--calendars--0--patch-1
   Merge from launchpad--devel--0

 * marius.gedminas@canonical.com/launchpad--devel--0--patch-1
   If database creation fails, tell the user why.

 * marius.gedminas@canonical.com/launchpad--devel--0--patch-2
   Remind users that you have to reload postgres after changing its cfg

 * marius.gedminas@canonical.com/launchpad--devel--0--patch-3
   Do not fail when 'launchpad_test_template' database doesn't exist

 * marius.gedminas@canonical.com/launchpad--devel--0--patch-4
   Check whether PostgreSQL is recent enough