fileList added to moduleList. Refs: #129.
This supports file names different form module names. All files of the specified subsystems are now listed in the result and with the correct file name, not the module name.
All subsystems, not only the specified set of subsystems, are now inspected in order to build the import dependencies.
Code cleanups as proposed by luowy.

Signed-off-by: Josef Templ <josef.templ@gmail.com>