Integration tests: Moving filter to filterable.
Filterable: Set the ID of the generated input as this.element.attr( "id" ) + "-filterable" if this.element has an ID set or "ui-filterable-" + this.uuid otherwise.
Integration tests: Filterable: Place test widgets on one page instead of multiple pages.
Filterable: Rename option "inputSelector" to "input" and adding option "children" to store the selector that identifies the children which should be filtered.
Filterable: Simplify filtering, and remove some special cases.
Filterable: Moving assumption about listview dividers into backcompat.
Filterable: the "children" option may be a function which returns a jQuery object.
Filterable: Backcompat: If widget and widget refresh() method is found, then call it after filtering.
Filterable: Backcompat: Move initial widget search to the first _filterItems() call.

This also removes the need to enhance-depend on the collapsible/controlgroup/selectmenu/listview.
Filterable: Do not generate ids.