STYLE: Easier maintenance of extension build system scripts

This commit updates the list of arguments to be alphabetically ordered
and be spread across multiple lines instead being on one long line very
hard to read.

This has been done by simply changing the single space into a line return
and sorting the list alphabetically using test editor functionality.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23529 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Fix usage of PYTHONPATH in extension launcher settings

Following r23036 environment variable specifying list of path are
handled differently. This commit ensures that python paths associated
with extension are also set consistently across Slicer application
and extension settings.

The additional extension launcher settings are used in macro
"slicer_add_python_test" and "slicer_add_python_unittest" implemented
in SlicerMacroPythonTesting.cmake module.

Since the macro "slicer_add_python_unittest" is used to configure the
generic tests from within the macro "slicerMacroBuildScriptedModule",
this commit should also help fix failing tests from extension bundling
scripted modules.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23530 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Fix IASEM extension tests ensuring ITKIOMRC factory is loaded

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23531 3bd1e089-480b-0410-8dfb-8563597acbee