consistency update

- OSspecific: chmod() -> chMod(), even although it's not used anywhere

- ListOps get subset() and inplaceSubset() templated on BoolListType

- added UList<bool>::operator[](..) const specialization.
  Returns false (actually pTraits<bool>::zero) for out-of-range elements.
  This lets us use List<bool> with lazy evaluation and no noticeable
  change in performance.

- use rcIndex() and fcIndex() wherever possible.
  Could check if branching or modulus is faster for fcIndex().

- UList and FixedList get 'const T* cdata() const' and 'T* data()' members.
  Similar to the STL front() and std::string::data() methods, they return a
  pointer to the first element without needing to write '&myList[0]', recast
  begin() or violate const-ness.

src/OpenFOAM/containers/HashTables/HashTable/HashTableI.H

@@ -54,7 +54,7 @@ inline Foam::label Foam::HashTable<T, Key, Hash>::size() const
 template<class T, class Key, class Hash>
 inline bool Foam::HashTable<T, Key, Hash>::empty() const
 {
-    return (nElmts_ == 0);
+    return !nElmts_;
 }