There is some trouble with dependencies around calendar/meeting. If I enable Calendar module and not Meeting (not required by calendar) I get lots of errors since the Contacts module assumes in several places that if Calendar is installed so is Meeting.
ModuleManager::is_installed('CRM/Calendar')!==-1)
changing that to
ModuleManager::is_installed('CRM/Meeting')!==-1)
on a few places (I changed 3 places, 1 in _0 and two in Common) seems to fix the errors. (But maybe Meeting should be required by by calendar also.)
