fix small bug in poisson_fft + new version of stretching operator encompassing the resolution of the linearized stretching equation

add SFD stuff (ie: method to get the filtered solution (=the base flow) needed to perform global linear stability analysis)

Update single precision patch. Add RMI example (need further tests, fix initial condition). Improve baroclinic operator.

All tests ok, except (as usual) :
 22 - mpi_test_advec_scales (Failed)
 79 - test_advection_nullVelocity (Failed)
 81 - test_advection_randomVelocity (Failed)
 85 - test_gpu_multiresolution_filter (Failed)
 86 - mpi_test_gpu_multiresolution_filter (Failed)

add hemisphere example + dump/restart in examples + add monitor printing velocity/vorticity profiles

Fix penalisation/subsets (partially)
Update doc (sphinx)
Almost all tests ok except:
	 22 - mpi_test_advec_scales (Failed)
	 77 - test_advection_nullVelocity (Failed)
	 79 - test_advection_randomVelocity (Failed)