CRM-12842 - Hide Volunteer Now button on event/info if user does not have register to volunteer permission. Fix VolunteerSignUp form to not throw fatal in postProcess when the role_id and need_id are not present in submitted values (this happens when the only public need is the one flexible need).
Merge pull request #106 from davecivicrm/CRM-12842b

CRM-12842 - Hide Volunteer Now button on event/info if user does not hav...