[IO] Remove unused ProjectData from XmlNumReader.

Also remove superfluous and wrong comments.
[IO] Correct includes. Include GEOObjects mostly.

Most of them are not needed anyway but GEOObjects.h.
ProjectData is needed in single place only.
[A] Move ProjectData from OGS to Applications.

This breaks some code. See following commits for recovery.
[A] Create ApplicationsLib.

This contains just ProjectData for now.
Correct ProjectData include. Link ApplicationsLib.
Merge branch 'SkeletonProjectData' into develop
[PL] Add mesh subset to initialize().
[PL] Initialize MeshSubsets and MeshComponentMap.
[PL] Rename mesh_items_all_nodes; items->subset.
[PL] Add destructor for GroundwaterFlowProcess.
[PL] Move mesh_component_map to class variables.

...from the initialize().
Also delete it in the dtor.
[PL] Add createDofMap() in Process.
[PL] Use number of node's DOF in createDOFMap().
[PL] Remove MeshComponentMap include from GW.
[PL] Add dof_map to GroundwaterFlow.
[PL] Empty solve().
[PL] Add empty GroundWaterflowFEM.
Merge branch 'GroundwaterFlow' into develop
First OGS simulation main program.
Adjust CMake config for command line application.

Previously added OGS directory holds the libOGS
and not the applications. This also separates
the libOGS library from applications.