Feature-Autocomplete Improvements

Autocomplete's custom javascript was getting quite big, and so every time you had an autocomplete on a page, you would get a lot of repeated javascript. This feature/enhancement does the following:
- moves the majority of autocomplete's javascript to a separate file so it gets included only once,
- adds an example of an autocomplete multi-select
- adds the ability to display html in the popup menu
- fixes some doc errors