--vtkweb-ports argument eliminated - Tangelo searches for free port in organic way now, automatically.

Closes #187.
Merge branch 'auto-vtkweb-ports'
Removing env var dependence on vtkpython location in favor of explicit command line argument.
Allowing a "vtkpython" field in the configuration file.

Closes #188.
Merge branch 'vtkpython-envvar'
Config file is expanded to full path so status report reads more informatively.
Added status attribute selectors.
Merge branch 'better-status'