ENH: update libs of etc/caseDicts/postProcess items
ENH: ensure destructor=default
ENH: ensure constness
ENH: ensure no 'copy construct' and 'no copy assignment' exist
TUT: add examples of function objects with full set
of settings into a TUT if unavailable
TUT: update pisoFoam/RAS/cavity tutorial in terms of usage
- Eg instead of using labelHashSet, used HashSet<label> which uses
the string::hash for hashing. Other places inadvertently using the
string::hash instead of Hash<label> for hashing.
STYLE: use Map<..> instead of HashTable<.., label, Hash<label>>
- reduces clutter
