Make a couple of tweaks to aid programatic CSS generation

* Add a new constructor for TermsList to allow for external
  code to generate them more readily
* Make the ToString generate a more human legible
  output
Only add newlines into the ToString() for friendlyFormat
Enhance user creation of TermList objects

* Exposes separator creation without exposing GrammarSegment
* Enables TermList creation by library users
Merge pull request #27 from jasonleenaylor/master

Make a couple of tweaks to aid programatic CSS generation