[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.
[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.