continued implementation of SWE_TsunamiScenario

1.) class is derieved from SWE_Scenario now
2.) most important functions have been implemented
3.) many new member variables

still todo: constructor, toGridCoordinates
Merge branch 'master' of https://github.com/farad91/SWE

Conflicts:
	src/scenarios/SWE_TsunamiScenario.hh