hdf5_der

[svn-r23892] 
The main functionality of writing to multiple dataset via H5Dwrite_multi() works in Parallel mode (collective and Independent IO).
This stage was given to Peter for testing via DAMSEL test cases.
Some more branched/sided functionalities need to be verified and worked on.

Working code, extra code and debugging code are added with ifdefs.
Those may be reused when working multi-dset read feature.
Extra code will be cleaned up at wrapping up stage later when all things work.
Debugging messages are turned off, so there is no debugging print outs when run tests.

This is based on HDF5 trunk r23325.