Added option to collapse groups (some kind of sub menu)

Add a placeholder using data-placeholder attribute

Fixed "All Selected" problem on non-multiselect with one option

added delimiter option to control the delimiter character for mouse-over

faq: add example of getting values dynamically

Add a placeholder using data-placeholder attribute so we don't need to create an entire function if we want to add placeholders to multiple multiselects.

Set to enabled on rebuild when options is not empty and disableIfEmpty is true.

There’s some situation when there are only one option and that displays
“All selected” which is only correct if the select tag is “multiple”.
In using this plugin for “single” dropdowns as well, there are
situations when there’s only one option and it shouldn’t show “All
selected”. This fixes that

Added option for #466 - although this may be handled easier by directly modifying the buttonText option!

Added the AMD header for use with require.js module definitions