simpleFoam: Added experimental "-postProcess" option

    Executes application functionObjects to post-process existing results.

    If the "dict" argument is specified the functionObjectList is constructed
    from that dictionary otherwise the functionObjectList is constructed from
    the "functions" sub-dictionary of "system/controlDict"

    Multiple time-steps may be processed and the standard utility time
    controls are provided.

This functionality is equivalent to execFlowFunctionObjects but in a
more efficient and general manner and will be included in all the
OpenFOAM solvers if it proves effective and maintainable.

The command-line options available with the "-postProcess" option may be
obtained by

simpleFoam -help -postProcess

Usage: simpleFoam [OPTIONS]
options:
  -case <dir>       specify alternate case directory, default is the cwd
  -constant         include the 'constant/' dir in the times list
  -dict <file>      read control dictionary from specified location
  -latestTime       s...