fixes #18

(Jak má člověk propalovat čas v Ostravě, když mu to školitel rozbil....
git log -L60,60:src/TNL/Meshes/GridDetails/Traverser_Grid3D_impl.h)

Even the methods for specializations without storage have to return
something, which was not the case...

Build of tools can be turned-off. Grid traversers for 1D and 2D has been rewritten using subdomain overlaps.

Add StaticVectorFor - for cycle doing all combinations of directions

Heavy Refactorization of DistributedGrids:
	-> Reordered Directions
	-> Add some useless Direction helper functions
	-> Set Up DistributedGrid_Base - shared base with dim template parameter
	-> Add support for communicationGroup created for DistributedGrid (MPI communicator support)

Code refactoring.

Added parallel reduction to communicators.

Added MPI info logs.

Only MPICommunicator and DistributedGrid is implemented.