Fix bug in HDF5/VTK output
Fix bug in field initialization
Modif in FD and diff operators

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

Adaptative vorticity projection according a given criterion + velocity correction (to prescribe proper mean flow and ensure the desired inlet flowrate) + some updates in adaptative time step procedure

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

improvement of the adaptative time step operator (the choice of dt_advection criterion now relies on the use of a method_key in a dictionnary)

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

Improvements : \n  - Removing GPU floats precision specification, use parmepy's globals.\n  - Add a wait GPU advection work variables (shorten the events list to wait for).

Improvements :\n -Automatic management of redistribute waitings in destination operators.\n -Redistribute transfers (MPI and OpenCL) could be seperated along vector components.\n -OpenCL kernels events use to synchronize GPU computations. \n -Examples update.