Add MethodChain refinement
Add roles dir to $LOAD_PATH
Extract PaginatedDataset to a separate role
Remove paginating context
Add ObjectWrap refinement
Scratch that, refinements won't help
Add methodchain
Add core exts
Add events filtering and roles
Use then_if in events filtering
Implemented course loading together with parallels.
Missing requires.
Removed duplicate columns in parallels table.
Implemented updating of already existing parallels.
Refactored TimetableSlot loading from KOSapi.
Implemented TimetableSlot updating.
Fixed semester code loading.
Renamed column type to parallel_type.
Fixed parallel type loading.
Dropped courses code column (already stored as ID).