ENH: InjectedParticleDistributionInjection  model - added protection for the case of zero particles; updated tutorial scripts.  See #363

BUG: Tutorial updates - updated rhoSimpleFoam thermo to use rhoThermo after commit a7c8d1cf - see #355

scalarTransport does not generate its own phiMean anymore but it is given from the user.
This "flux" can be generated using the "flux" FO

- fixed library path for VTK.
  They should use lib/ and not lib64/

- cleanup some code in foamInstallationTest

    fieldName.endsWith("_0")
vs
    fieldName.size() > 2 && fieldName(fieldName.size()-2, 2) == "_0"

- As the names describe, check if the string starts or ends with a
  particular value. Always true if the given text is empty or if the
  string is identical to the given text.

   - add an extension to the file name
   - remove a file extension
   - check if a file name has an extension
   - check if a file name has a particular extension (as word),
     or matches a particular grouping of extensions (as wordRe).

This slightly more convenient when working with char[] input:

     fileName file1{ "path", "name", "to", "file.ext" };
vs.  fileName file1 = fileName(path)/"name"/"to"/"file.ext";

But is a bit more efficient since it avoid most of the intermediate
copying and resizing incurred by the '/' operator.

- not required for ASCII, and makes normal dictionaries too noisy.

STYLE: move archHint to be a file-scope static

- Use wordRe::REGEXP (not wordRe::DETECT) if the content is known to
  be a regular expression anyhow.

Bounding thermo.rho in rhoPorousSimpleFoam.
Changing initial time step in externalSolarLoad tutorial.
Commenting out momemtun source term in steamInjection which causes problems