ENH: writing and reading multiple iterations with SIONlib

ENH: new mode binary_with_folders creates processor folders for POSIX I/O

STYLE: moved printing into seprate functions
STYLE: moved data size calculations into Settings class

Again bug fix for adios2 reading.

BUG: fixing parsing pointer of temporary copy of std::vector<double> in adios2::Engine::Put

- Set explicit barriers for benchmarking.
- Refactored measurment output.
- Enable removing file. (Caution with large jobs that spend extra time in file removal.)

Absolute offsets in MPI_File_write_at are not avoided for now. Hence, the file size is limited.

And some more bits of refactoring.

Note that the time steps are stored as ADIOS2 steps.
ADIOS2 steps do not enable random access during streaming mode from BP file.

And updating file pointer for MPI_File_write and MPI_File_write_at to store several time steps in one file.

Three MPIIO examples have been added respectively based on MPI_write, MPI_write_at, and MPI_write_all.
Added IO performance measurment which is controlled by two additional command line arguments:
- number of writes to be measured
- number initial writes to skip during measurement
(See also the ReadMe.md)