update #346
 - added parameter respect_partition
 - set it in ImporterGmsh
remove whitespaces
make subworlds and associated function const
and M_subworlds mutable
use mesh worldComm in addRegions() instead of Environment::worldComm()
this avoid a deadlock
update #346
 - update example pmesh.cpp, it can be run in parallel but the actual code is
 run on the master processor
@asamake that's what you want for the parallel coarse preconditioner