General features

The general (final) features before the first stable version will include:
- System for recording marks in various subjects, allowing users to load/save from/to a XML file.
  * (In)sufficient/good marks will be marked by a color code: [0,5.5> is red, [5.5,8.0> is black, [8.0,10.0] is green.
  * Weighted averages will automatically be calculated.
  * There'll be the ability to create new lists and edit existing ones.
  * The list of marks is saved to a XML file which can be opened again to add new marks.
- Planning homework via a special agenda.
  * If a timetable is filled in, data will be used to automatically display the subject for a period.
- Managing timetables.
  * Enter subject, period and classroom.
- Managing telephone circles.
  * Create new telephone circles based on the times people leave their homes to notify students timely of changes in the timetable.

Everything will be saved in different XML files. In the future, Preferences will also be implemented.