Accessing to particle container stored in CUDS-hdf5 file [WIP] 

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

In this PR, DataContainer is not integrated in FileParticleContainer.

Todo:
- [x] add benchmarking
I was having a problem with numexpr when I placed it in requirements.txt.  I will look into this again next week to see if I can get it straightened out.