Added JSDocs to the UrlGenerator class
Added JSDocs to the UrlGenerator class

refs https://github.com/TryGhost/Toolbox/issues/127

- Before refactoring the URL Generator constructor to have a smaller construcotr, documented current state for future reference

e10/Ghost,ErisDS/Ghost,e10/Ghost,ErisDS/Ghost,TryGhost/Ghost,TryGhost/Ghost,TryGhost/Ghost,ErisDS/Ghost