add diagnostics + pep8 + remove import relative paths

Examples/NavierStokes3d.py

Examples/NavierStokes3d_sphere.py

Examples/NavierStokes3d_vortRing.py

Examples/input.dat

Examples/oarscript.sh

HySoP/hysop/__init__.py.in

HySoP/hysop/integrator/euler.py

HySoP/hysop/integrator/runge_kutta2.py

HySoP/hysop/integrator/runge_kutta3.py

HySoP/hysop/integrator/runge_kutta4.py

HySoP/hysop/obstacle/obstacle.py

HySoP/hysop/obstacle/obstacle_d.py

HySoP/hysop/operator/advec_scales.py

HySoP/hysop/operator/advec_scales_d.py

HySoP/hysop/operator/differentialOperator.py

HySoP/hysop/operator/differentialOperator_d.py

HySoP/hysop/operator/diffusion.py

HySoP/hysop/operator/fct2op.py

HySoP/hysop/operator/multiphase.py

HySoP/hysop/operator/multiphase_d.py