- also split on colons for consistency

This reverts commit c5bea524.

This reverts commit 2e1e671d.

- the path is accesible either way, but use setenv for consistency with
  other environment variables. It also simplifies foamCleanPath again.

- this allows more direct use by c-shell

- Also adjusted formatting of usage to match what argList generates

- old-style (left untouched for now):
  app, lib, run, sol, tut, util

- new-style:
  foamApps, foamLib, foamRun, foamSol, foamTut, foamUtils

- additional aliases:
  userApps, whichFoam

NB: ideally we'd have 'foamSrc' instead of 'src'.
    Do we really need 'foamsrc' and 'foamfv' anyhow?

The call to foamCleanPath from etc/{bashrc,cshrc} passes all the wildcards
together as a single argument - causing nothing to be cleaned.  Now split
the args on whitespace. Also added more IFS hacking to reduce forking.