- createFields extends potentialFoam
- (so registers 'p' field, same as potentialFoam)
- writephi is optional as in potentialFoam

transformation support in-place modifies the data (e.g. to
add a transform). This might cause the neighbour side patch
to pick up owner side information.

ENH: MeshObject: specify name (instead of typeName)

See merge request !589

- std::to_string(double) is locale sensitive.

- wish to deprecate and remove exprFixedValue in the future since the
  same functionality is possible using patch expressions with a
  uniformFixedValue condition.

- make available as normal()

- skip loading of fields with -no-internal, -no-boundary

- suppress reporting fields with -no-internal, -no-boundary

- cache loaded volume field for reuse with point interpolation.
  Trade off some memory overhead against reading twice.

  NOTE: this issue will not be evident with foamToEnsight since there
  it only handles cell data *or* point data (not both), so a field is
  only ever loaded/processed once.

- This simplifies definition of 'lazier' (READ_IF_PRESENT)
  construction or assignment.

  For construction:
    - For MUST_READ and key not found: FatalIOError.
    - For LAZY_READ and key not found: initialise field with Zero.
    - For NO_READ and key not found: simply size the field.

  For assignment:
    - If len == 0 : a no-op and return True.
    - For NO_READ : a no-op and return False.
    - For MUST_READ and key not found : FatalIOError

- encompasses isReadOptional or isReadRequired check

STYLE: allow LAZY_READ as a shorter synonym for READ_IF_PRESENT

- add helper for downgrading MUST_READ... to LAZY_READ

- was missing evaluateCoupled on the initial faceAreaNormals field
  (related to #2507)

- replaces getOrDefault/readIfPresent for "patchType"

- remove redundant raw patch slice and non-const patchSlice, which
  were only used internally by finiteArea.

STYLE: noexcept on more patch methods

- with geometryOrder=1, edge normal calculation is done directly from
  the faces, whereas geometryOrder=2 they are calculated based on the
  point normals of each end.

  In both cases, the geometry calculation uses processor communication
  (with corresponding waitRequests etc).

  Since the final correction and the halo face normals also need
  collective communication, these routines must be triggered on all
  processors or they will block. Thus also include edgeAreaNormals()
  triggering in addition to pointAreaNormals() triggering.

- handle lower geometryOrder values directly within edgeAreaNormals()
  and reuse the results within Le().

- direct nonBlocking recv/send of edge normals instead using the
  intermediate processorLduInterface buffers

- symmetrical evaluation for processor patches, eliminates
  scalar/vector multiply followed by projection.

STYLE: use evaluateCoupled instead of local versions

- adjust looping to resemble LIFO pattern

STYLE: adjust some string includes

- returns reference as per C++17 std::vector

STYLE: drop unused, redundant DynamicField remove() method

ENH: support UIPstream::read, UOPstream::write with UList, SubList

- vector, tensor versions are defined component-wise
  to avoid intermediates.

  The base version uses the form "(1-t)*a + t*b" without any bounds
  checking (ie, will also extrapolate).

- proper component-wise clamping for MinMax clamp().

- construct clampOp from components

- propagate clamp() method from GeometricField to FieldField and Field

- clamp_min() and clamp_max() for one-sided clamping,
  as explicit alternative to min/max free functions which can
  be less intuitive and often involve additional field copies.

- top-level checks to skip applying invalid min/max ranges
  and bypass the internal checks of MinMax::clamp() etc.

- simplifies addressing within sub-ranges.
  Clamps the access range directly

- reuse dimensionSet checking for dimensionedType

STYLE: unfriend some functions for complex

GIT: primitives/compat with compatibility includes
GIT: primitives/traits with pTraits, contiguous, zero, one etc.

COMP: relocate base equal(a,b) definition from scalar.H -> label.H
- make more universally available

STYLE: replace occasional use of notEqual(a,b) with !equal(a,b)

- avoids implicit promotion of label to scalar for no-op,
  or alternatively promotion of symmTensor to tensor for no-op
  (ie, ambiguous).

- fix incorrect transform(.., symmTensor, ...) declarations.

STYLE: pTraits::rank instead of std::is_arithmetic to suppress transform

- more consistent with doTransform() coding, potentially useful for
  complex

STYLE: rename some internal buffers with the data types

  low-level  : byteSendBuf_, byteRecvBuf_
  field level: sendBuf_, recvBuf_
  solve level: scalarSendBuf_, scalarRecvBuf_

- with alternative faceCell addressing, use the three-parameter
  version only. This avoids potential future ambiguity with the
  two-parameter version (eg, with a label type)

ENH: add faPatchField patchInternalField() for symmetry with fvPatchField

ENH: direct reference to mesh thisDb instead of inferring

ENH: pointMesh::boundaryMesh() method (eg, similar to fvMesh)

- Only wait for locally invoked requests.
  Reflects behaviour of lduMatrix update.

- UPstream::Request wrapping class provides an opaque wrapper for
  vendor MPI_Request values, independent of global lists.

ENH: support for MPI barrier (blocking or non-blocking)
ENH: support for MPI sync-send variants

STYLE: deprecate waitRequests() without a position parameter

- in many cases this can indicate a problem in the program logic since
  normally the startOfRequests should be tracked locally.

- reduces clutter. In some cases the Fwd typedefs were also incorrect

STYLE: combine Scalar specialisations into corresponding PatchFields.C

- reduces clutter, simplifies future adjustments

- simplifies code, consistent with other matrix transfer functions.
  Use a setter method.

STYLE: AMIInterpolation::upToDate(bool) setter method

ENH: add guards to avoid float-compressed transfer of integral types

STYLE: drop unused debug member from abstract interface classes