RE 6866, Update property names used in MantidEV

The property names of parameters passed to OptimizeCrystalPlacement
are now updated to the new parameter names.
Fixed some Doxygen warnings.
Adjusted some labels on the GUI to be clearer, based on
comments from potential users.

refs #6866
Merge branch 'feature/6866_FixMantidEVPropertyNames' into develop