See #25

Fixes #30

TODO: it should be added to other formats as well

The constructor makes a shallow copy, not a deep copy.

Hamilton jacobi

See merge request !27

Lbm

See merge request !26

Some of them are just turned off and need to be fixed properly later.

It is either from subdomain boundary to overlap or vice versa.

Added macro TNL_MPI_PRINT_COND for conditional print outs.