Minor code reformatting + Extended README 

Could you please merge these changes? They have been tested on ARM and do not break tests.

* Cleaned up whitespace in jonesforth.S, replaced the current mix of tab and spaces with a space-only version. Also removed trailing whitespaces.

* Fixed some obsolete comments and typos.

* Added a reference to Rosetta Code in ``test_nqueens.f``.

* Merged pull request 14 changes.

* Improved README