Return values are nicer than modifiable parameters. This also avoids the
circular dependency between TNL::String and List.

This is much simpler than using the C functions. As a bonus, I/O errors
throw exceptions.

Reimplemented Config::ConfigDescription and Config::ParameterContainer using std::vector instead of TNL::List

This is much safer and simpler because it solves many problems due to
cyclic inclusion of TNL headers.

Having 4 different files (Cuda.h, Cuda_impl.h, Cuda.cpp, Cuda.cu) for
one class is not clear at all. On a related note, a class with 28
methods is clearly too long to be considered as well-designed, so it
should be split into several subclasses. Obviously, the full CUDA
support cannot be provided/wrapped by a single class so the design
should be more flexible.

This will fix the bugs described in the FIXME notes.

Compilation fails due to cyclic dependency between the headers, it will
be fixed later.

TNL is not supposed to have any external dependencies, so an empty
config file is useless. If some marginal parts of the project (such as
code for image processing) need to depend on some non-standard library,
they should be split into a separate module/project so that the
dependencies can be properly specified.

For now, the macros are specified as compiler parameters. Client
software using the affected headers will have to do the same.

They are part of POSIX so they should work on anything but Windows. This
can be checked simply by a predefined macro, configuration during build
is not necessary. See https://stackoverflow.com/a/4575466 for reference.

MPI: refactoring of DistributedGridSynchronizer

See merge request !21

Vít Hanousek authored Nov 22, 2018 and Jakub Klinkovský committed Jan 25, 2019

	- added compatibility code for periodic-BC
	- this part of code needs discusion if work corectly

Vít Hanousek authored Nov 22, 2018 and Jakub Klinkovský committed Jan 25, 2019

	Issue #15 working basic synchronizer
	-Periodic BC doesnt work

Vít Hanousek authored Nov 22, 2018 and Jakub Klinkovský committed Jan 25, 2019

 have same sizes at standard communication.
 -distributedGridSynchronizer was moved.

Vít Hanousek authored Nov 21, 2018 and Jakub Klinkovský committed Jan 25, 2019

	- without PeriodicBC implementation
	- SubdomainOverlapGetter has changed interface
	 -> need more updates, only basic grid tests work

Vít Hanousek authored Nov 21, 2018 and Jakub Klinkovský committed Jan 25, 2019

bad interpretation of lower and upper overlap.

Vít Hanousek authored Nov 21, 2018 and Jakub Klinkovský committed Jan 25, 2019

   -rename directions to ZvYvXv, where v is m,z,p
   -correct y direction in 2D

Nina

See merge request !19