I migrated the widget factory docs as described.
This fixes #209
added the How jQuery UI Works page as well as the jQuery UI section
added jQuery UI: How to use the Widget Factory
Changed the filename for how to use the widget factory as it had an e…
…xtra d in the name
added why use the widget factory and updated the order of the pages t…
…o reflect reability
Updated the jQuery UI Intro text a bit.
Merging #220 into ui-docs branch - @redwolves Issue #209: Migrated Wi…
…dget Factory Docs
heh, love that it didn't show that i pushed that, not you ;)
Anyway, moving this content into the ui-docs branch (#230) so we can look over it in one place.