in decomposeParDict.
This default number of processors may be overridden by the new "-np"
option to runParallel which must be specified before the application
name e.g.:
runParallel -np 4 pisoFoam
For multi-region cases the default location of blockMeshDict is now system/<region name>
If the blockMeshDict is not found in system then the constant directory
is also checked providing backward-compatibility