Refactor Typeahead prototype
Attach mouse events to each item of the list
Fix some bugs in moveover event
Refactor private method onmouseover
Refactor private method onmouseout
Refactor method append of ItemList
Refactor class ItemList
Rename some methods
Fix some bugs for version 0.1.0
Fix behavior of autocomplete option without items selected
Allow a function that returns item list as source