Add Surfaces object checks
The following checks were added:
- BoundaryCheckTests.cpp
- LineSurfaceTests.cpp
- RectangleBoundsTests.cpp
- SurfaceBoundsTests.cpp
- SurfaceTests.cpp
Which required 'stub' implementations of the baseclasses which were tested, and some scaffolding:
- LineSurfaceStub.hpp
- SurfaceStub.hpp
- DetectorElementStub.hpp
In some cases tests are marked as 'expected to fail', however these reflect real issues which should be addressed.