- make the purpose more explicit, and reduces some work for the
  compiler as well.

- both autoPtr and tmp are defined with an implicit construct from
  nullptr (but with explicit construct from a pointer to null).
  Thus is it safe to use 'nullptr' when returning an empty autoPtr or tmp.

Improve alignment of its behaviour with std::unique_ptr

  - element_type typedef
  - release() method - identical to ptr() method
  - get() method to get the pointer without checking and without releasing it.
  - operator*() for dereferencing

Method name changes

  - renamed rawPtr() to get()
  - renamed rawRef() to ref(), removed unused const version.

Removed methods/operators

  - assignment from a raw pointer was deleted (was rarely used).
    Can be convenient, but uncontrolled and potentially unsafe.
    Do allow assignment from a literal nullptr though, since this
    can never leak (and also corresponds to the unique_ptr API).

Additional methods

  - clone() method: forwards to the clone() method of the underlying
    data object with argument forwarding.

  - reset(autoPtr&&) as an alternative to operator=(autoPtr&&)

STYLE: avoid implicit conversion from autoPtr to object type in many places

- existing implementation has the following:

     operator const T&() const { return operator*(); }

  which means that the following code works:

       autoPtr<mapPolyMesh> map = ...;
       updateMesh(*map);    // OK: explicit dereferencing
       updateMesh(map());   // OK: explicit dereferencing
       updateMesh(map);     // OK: implicit dereferencing

  for clarity it may preferable to avoid the implicit dereferencing

- prefer operator* to operator() when deferenced a return value
  so it is clearer that a pointer is involve and not a function call
  etc    Eg,   return *meshPtr_;  vs.  return meshPtr_();

- this is a provision for defining execute actions that can be called
  largely independently of the normal time-loop constraints. This can
  be useful to provide hooks for sub-cycling, or to define an action
  that can be triggered manually or on some other event.

Fixed by setting flag which then gets queried by Time. Fixes #420.

- cf. Line 224 of timeControl.C

Patch contributed by Bruno Santos
Resolves patch request http://bugs.openfoam.org/view.php?id=2355

Requires gcc version 4.7 or higher

Replaced the 'postProcess' argument to the 'write' and 'execute'
functions with the single static member 'postProcess' in the
functionObject base-class.

e.g.
    postProcess -func 'patchAverage(name=inlet,p)'
    postProcess -func 'patchIntegrate(name=inlet,p)'

e.g.

functions
{
    libs ("libfieldFunctionObjects.so");

    div
    {
        type            div;
        field           U;
        executeControl  writeTime;
        writeControl    writeTime;
    }

    Q
    {
        type            Q;
        executeControl  writeTime;
        writeControl    writeTime;
    }
}

   the equivalent functionality is provided by the writeRegisteredObject
   functionObject in a MUCH simpler, easier and extensible manner.

functionObject: Removed the now redundant 'timeSet' function.

This changes simplifies the specification of functionObjects in
controlDict and is consistent with the 'libs' option in controlDict to
load special solver libraries.

Support for the old 'functionObjectLibs' name is supported for backward compatibility.

  - Avoids the need for the 'OutputFilterFunctionObject' wrapper
  - Time-control for execution and writing is now provided by the
    'timeControlFunctionObject' which instantiates the processing
    'functionObject' and controls its operation.
  - Alternative time-control functionObjects can now be written and
    selected at run-time without the need to compile wrapped version of
    EVERY existing functionObject which would have been required in the
    old structure.
  - The separation of 'execute' and 'write' functions is now formalized in the
    'functionObject' base-class and all derived classes implement the
    two functions.
  - Unnecessary implementations of functions with appropriate defaults
    in the 'functionObject' base-class have been removed reducing
    clutter and simplifying implementation of new functionObjects.
  - The 'coded' 'functionObject' has also been updated, simplified and tested.
  - Further simplification is now possible by creating some general
    intermediate classes derived from 'functionObject'.

to have the prefix 'write' rather than 'output'

So outputTime() -> writeTime()

but 'outputTime()' is still supported for backward-compatibility.

Also removed the redundant secondary-writing functionality from Time
which has been superseded by the 'writeRegisteredObject' functionObject.

functionObjects: Changed options 'outputControl' -> 'writeControl' and 'outputInterval' -> 'writeInterval'

for consistency with the time controls in controlDict and to avoid
unnecessary confusion.  All code and tutorials have been updated.

The old names 'outputControl' and 'outputInterval' are but supported for
backward compatibility but deprecated.

Simplified and generalized the handling of functionObjects which fail to
construct by removing them from the list rather than maintaining an
"enabled" switch in each functionObject.

execFlowFunctionObjects: Replaced with script providing instructions to use the '-postProcess' option

functionObjectFile provides basic directory, file and formatting functions
functionObjectFiles provides multi-file cache

The new NotImplemented macro uses __PRETTY_FUNCTION__ for GNU compatible
compilers otherwise __func__ to provide the function name string.

    Time::adjustDeltaT(). It allows function objects to manipulate the time step to
    dump at adjustable times. The following options are available for output in
    function objects: timeStep, outputTime, adjustableTime, runTime, clockTime
    and cpuTime.

end of Time::operator++. This allows to know if the next timeIndex will be
a dumping time. The function object "partialWrite" modifyes the write option
of the those fields which will be written down at given intervals of the overall
outout times.

This reverts commit c5bea524.

This reverts commit b18f6cc1.