Added support for database, Updated Utilities

Utilities:
+ listOptionalSubjects
+ listClasses
+ getFilePath
Merge branch 'master' of https://github.com/micprog/MNGTimetable

Conflicts:
	MNGTimetable.xcodeproj/project.pbxproj
	MNGTimetable/ClassPicker.m
	MNGTimetable/FirstViewController.m