Accessing to particle container stored in CUDS-hdf5 file 

This PR proposes a general module for accessing CUDS files stored in a hdf5 file.  This PR illustrates what was proposed on the [wiki at (CUDS_FILE)](https://publicwiki-01.fraunhofer.de/SimPhoNy-Project/index.php/CUDS_File) but this PR only includes work related to particle containers:
* Cuds_File:  module to access the CUDS-hdf5 file 
* FileParticleContainer:  a class to access a specific particle container stored in the CUDS-hdf5 file

`return self._file and self._file.isopen` will do the same thing for this function