Menu: Documenting how dividers can be created.
Autocomplete: Clarify that autocompletes can be created on <input>, <textarea>, or [contenteditable] elements.
Theming: Add theming documentation for individual widgets. Fixes #137.
Datepicker: Note that the buttonImage option must be used with the showOn option, and that the buttonImageOnly option must be used with the buttonImage option. Fixes #146.
Datepicker: showButtonPanel - Explain what the button panel this option shows actually is.