Preapare Distributed Grids for Communication groups (aka MPI Communicator)

Added command line arguments for a grid domain decomposition setup.

TNL compiles with MPI by default.

TNL compiles with MPI by default.

TNL compiles with MPI by default.

Only MPICommunicator and DistributedGrid is implemented.

Allow existance of non setup synchronizer object. MeshFunction creates grid synchronizer automagicli with binding.
(only if distr grid was chnged)

There is shor test of this stuff for 1D 2D and 3D.

Relpaced tabs with 4spaces.

Improve of DistributedGrid: Distributed grid teak overlap size as parameter.

Test 3Ddistribuovaného gridu. Chybí test sousedů, je limitován na 27 procesorů, netestuje 1D či 2D distribuci nodů.

Lihgt refactorization of 1D and 2D distributedGridSynchronizer. Now hav same interface as 3D distributedGridSynchronizer and function Synchronize is lighter.

1)Traversar writes to Boundary -- known BUG - this travarsar will write boundary condition in overlap too -- test is forcet to accept this
2)Traversar writes to Interior entities
3)Traversar writes to Allentities
4)Traversar writes its rank into AllEntities and then mesh si synchronized. Check Overlaping entities that data come from correct neibrouh
5)Traversar writes Linear function into AllEntities and then mesh is synchronized. All entities are checked that it has correc value.

Limitations:
Test run only on 9 process by code -> only regular 2D distribution of process is checked. Linear distribution is not chceked.
Test run only for double as RealType of DOF.
Only one size of global mesh is tested.