przewozy regionalne getAvailableLines, minorfixes

- added a testcase for Przewozy Regionalne as no train is currently
ongoing, so I needed something to work on - a snapshot of PR page from
earlier today
- implemented getAvialableLines in PrzewozyRegionalne
- minor license fixes
finished PR data source

- implemented getPosition & getAllPositions in PR
- implemented getAllPositions in Positioner for classess that do not
have a specialised getAllPositions function