Use customized version of RolePlaying

Some paths may end-up without AS being loaded,
which causes RP to fail.
Fix Pliny dependencies in spec helper
Add ApiHelper specs for user_allowed?
Check for wildcard superuser
Merge pull request #69 from cvut/token_wildcard

Superuser access token
Rename EventPlanner to SemesterCalendar.
Remove useless TeachingTime <-> SemesterCalendar two-way dependency.
Introduce proper EventPlanner and move all event planning logic into it.
Remove unused Semester class.
Replace ScheduleManager planning specs with EventPlanning specs.
Parsing starts_at and ends_at strings in Event fabricator.
Add + operator to Period.
Refactor EventPlanner#renumber_events and add specs.
Change Event renumbering implementation to SQL.