[SYM,BB10] Switch with Arrival and Via station wasn't working correctly.
Made some improvements to Trainrestrictions model:

- no need to mark methods as Q_INVOKABLE as they're not used in QML;
- removed unneeded reimplementations as they already do the same in the
  parent QStringListModel class;
- removed unused method data(int index).
Fixed compilation warning:

'Fahrplan::m_dateTime' will be initialized after 'int
Fahrplan::m_trainrestriction'.
[SYM,BB10] Inverted style wasn't applied to favorites star position label.
Merge pull request #77 from leppa/master

Few fixes and improvements