* Added tipsy library

* Added tipsy library
* Added associated files for tooltip display
* Added associated css rules for tooltip display
* Updated installer's help system in (most?) places to display help as tooltips instead of show/hide system
* Beginnings of visual changes (e.g., less boxes, more color)
* Modified several of the installer's widget display methods
* Added a couple new i18n values
* Fixed small bug in installer logic:
  - Password validation on new users was being executed even if there wasn't a $user object