[A] Add ProjecData::processes iterator interface.
[PL] Add Process interface for solve() and post().
[A] Initialize and solve processes from main.
[PL] GW: Add solve() and post() skeltons.
[PL] Add createDofMap() in Process.
[PL] Use number of node's DOF in createDOFMap().
[PL] GW: Add MeshSubsets and MeshComponentMap.
[PL] GW: Add _dof_map, calling createDofMap.
[PL] GW: Show future usage of the _dof_map.
Merge pull request #516 from endJunction/CreateDofMap

Create dof map
Merge pull request #517 from endJunction/Skeletons

Adds solve, post function skeletons for processes and calling them from main.
[PL] Add mesh node ids for BoundaryCondition.
[PL] Initialize node ids vec in boundary conditions.