Implemented NPM packaging

 - Remove the local copy of the diff-match-match fork;
   declare it as a dependency instead
 - Remove all generated files from the GIT repo (JS and sourcemap files)
 - Remove ad-hoc scripts
 - Rename dom_text_mapper.coffee to text_searcher.coffee
   (we have nothing to do with the DOM any more)
 - Publish NPM module as fuzzy-text-search-h