Back to previous commit to (try to) fix bug in git : it loses all history in case of file/rep renaming.

24 - test_opencl_environment (Failed), because of pep8
Examples not tested but NSDebug.py which works fine.

Add baroclinic operator and associated example for RTI benchmark (which is still not working properly) + some documentation + several addings/improvements  

general updates concerning NS benchmark with bluff bodies (flow past sphere, etc ...) - still some problems to solve ...

Documentation related to velocity correction (flow rate prescription at the oulet of the box-domain ...)

general updates with in particular, simulation with adaptative time step, script for flow past bluff bodies, forces computation

array data
Change of structur of Stretching Operator to used RK and Euler Generic