ENH: extend rmDir to handle removal of empty directories only
- recursively remove directories that only contain other directories
but no other contents. Treats dead links as non-content.
- include constant/faMesh cleanup (cleanFaMesh) as part of standard
cleanCase
- simplify cleanPolyMesh function to now just warn about old
constant/polyMesh/blockMeshDict but not try to remove anything
- cleanup cellDist.vtu (decomposePar -dry-run) as well
ENH: foamRunTutorials - fallback to Allrun-parallel, Allrun-serial
TUT: call m4 with file argument instead of redirected stdin
TUT: adjust suffixes on decomposeParDict variants
