fixed issue where dem nodes could be located below mesh bottom in prism meshes
correctly cleared reserved mem again
resolved dem-nodes below bottom layer for tet mesh generation
adjusted sequence of layers in dialog and LayeredVolume
removed double const
fixed implicit conversion
Cleanup, documentation.
[A] Change linkage of ProjectData detail::readGeometry to internal.

Clears a warning from the compiler about missing prototope.
[A] Disable copy-ctor of ProjectData.

An implicitly created one makes the code
ill-formed because of the user-defined constructor.
changes based on pr comments
added time measuring for subsurface mesh construction
moved node construction for new layers to base class
Merge pull request #532 from endJunction/Cleanup

Cleanup
added documentation for new method
added include
Merge pull request #528 from rinkk/SubsurfaceDemConflict

[Fix] Subsurface DEM Conflict