Remove some ambiguity:

* Use 'worker' instead of 'worker process'
  + This helps a bit because we use the word 'process' in many senses
* Use 'coordinator' instead of 'fitting process'
  + Previously the word 'fitting' was used to describe both the fitting
    metadata and, occasionally, in place of 'fitting process'
* Introduce the 'sink' concept earlier
* Minor rewordings in other cases to remove ambiguity about antecedents
Missing erlang source specification - fix so HTML export works
Escape underscores in headers so exports to HTML work properly
Broken link
Fix new section title now that fittings process is no more
Test fix for underscore escaping problem
Replace all escaped underscores in headers with =..= for code references
Update comments to match new README - s/fitting/coordinator/ where appropriate
Update comments to match new README - s/fitting/coordinator/ where appropriate
s/fitting process/fitting coordinator/ (and spurious whitespace that Emacs removed)
Merge pull request #66 from branch 'macintux/readme-updates'