- Tweaked abstract slightly. ...

- Added labels to all sections.
- Added figures.

- Tidied up appearance of a few references. ...

- Fixed a couple of minor errors.
- Removed the really long URLs --- most were unnecessary anyway.

- Added BibTeX database and fixed up references section (hope I got ...

them all correct!).

- Straight dump of text from original Word document with only special ...

characters and basic formatting fixed. References are currently in
  a woeful state :)