- reduced clutter when iterating over containers

- in 1812 propagated through the distinction between areaNormal and
  unitNormal (issue #885).

  In older versions, the normal() always meant the area-normal for
  certain of these primitive.

  However, the .org version changed this to now return the unit-normal
  instead, but with the same method name. Thus add the deprecated
  message to avoid future inadvertent uses of normal() without being
  certain which one is being meant.

- a valid() method (same as !empty() call) for consistency with other
  containers and data types

- a centre() method (same as midpoint() method) for consistency with
  other OpenFOAM geometric entities

- move constructors, construct from std::pair
- input/output of std::pair

Makes it easier when using data structures for other codes.

Had this:

    Tuple2() {}

Instead of:

    Tuple2() : f_(), s_() {}

which is the same as

    Tuple2() = default;

This meant that Tuple2<scalar, scalar>() was not being zero-initialized

- reduced clutter when iterating over containers

- a FixedList is generally small so there is little advantage
  in a compact output form for uniform content.  Eg, "2{-1}"

  By avoiding this compact form we obtain output that is also
  consistent with Tuple2, for example.

- make FixedList construct from Istream explicit

- relocate the pair_entry (HashTable) and unary_entry (HashSet) into
  the Detail namespace and add output handling.

  The output handling at this level removes the reliance on zero::null
  output (HashSet) and allows direct support of pointers.
  This means that the following now works

      HashTable<T*> tbl;
      os << tbl;

  It also means that we don't need to overload operator<< for
  HashPtrTable anymore.

- avoid delete/new when calling HashSet::set(). If the entry already
  exists there is no reason to remove it and add another one with the
  same content.

STYLE: HashTable iterators now have a val() method

- identical to the object() iterator method, but shorter to type.

- fixed some more places with an explicit AUTO_WRITE.

BUG: revert handling of the readOption. It should not be NO_READ.

  In cases where the user a IOobject without specifying read/write, it
  defaults to NO_READ anyhow. However, the move constructor can also
  be called with empty lists and a read option. This has the same
  signature, but obviously will not work with NO_READ.

- uses the value of foamVersion::api, which should be reliable.

- identical to found(), which should be used for more consistency.
  The contains() is a remnant from when hashedWordList was generalized
  from a speciesTable (OCT 2010)

- and support setting cmake_version within the paraview config files

- looks slightly messier without associative arrays, but improves
  portability. Should now also work with dash.

STYLE: support wmakeBuildInfo -cmp and -check options as equivalent

- applies to HashTable and Linked-Lists

- deprecate the Linked-List iterator found() method, since this makes
  less sense (linguistically)

- a holdover from introducing the endBlock() method

- provide a lookupOrDefault constructor form, since this is a fairly
  commonly used requirement and simplifies the calling sequence.

  Before

      dimensionedScalar rhoMax
      (
          dimensionedScalar::lookupOrDefault
          (
              "rhoMax",
              pimple.dict(),
              dimDensity,
              GREAT
          )
     );

  After

      dimensionedScalar rhoMax("rhoMax", dimDensity, GREAT, pimple.dict());

- read, readIfPresent methods with alternative lookup names.

- Mark the Istream related constructors with compile-time deprecated
  warnings.

BUG: read, readIfPresent methods not handling optional dimensions (#1148)

STYLE: use standard dimensionedSets