Small error fixes.

 * force transferred in MPI comms
 * started cleanup of streaming code

 * updated pressure force calculation of squirmers

y-boundaries must be enabled before z-boundaries can be used

if y and z walls are enabled, too many particles are intialzied per core

** ensure that $PYTHONPATH is set properly
** executing python/pyro/expose_pyroclasses.py now does the same as the old pyro mode
++ scons correctly parses input arguments now
++ vs code project settings improved