Added a variable to track groups vs. files.

* A new id number for the handle has been added
  to decipher between groups and files.
  Certain operations (enddef/redef) require that
  the file-id is passed, others just need the
  group id.

* Added parallel functions to determine the actual
  parallelisation utilised.

* Made all tests objects PHONY so that make always
  creates them.