case-insensitive filtering.

Signed-off-by: Mathieu Doyon <mathieu.doyon@studiofrenetic.com>

Fixed #73.

Fixes ie filtering bug.

Added the selectAllValue option to change the value by which the select
all option is identified. Cosmetics.

Fixed an issue concerning the refresh method and the unfocussing of the
filter search input after filtering the options.

Updated documentation: includeSelectAll, selectAllText, selectedClass,
enabledFiltering and filterPlaceholder options. Updated the README.
moved the filter initialization to the buildDropdown method. The rebuild
method has to remove the search field, too, otherwise it will be
duplicated.

Added support to override/extend default options.

Fixes knockout integration issues.

Added filtering capability.

added css class to the 'select all' option.

Made refresh() update disabled state.

added a reference to the constructor so I can override the default options when initializing multiselect with data-role attribute

Stop propagation for touch devices, too.

Fix single selection issue.

Fixes knockout integration issues.

we dont need to call $('#element').multiselect() before ko anymore

Added selectAll option and demos. Further cosmetics, comments etc. .

Normalize prop access

Removed browser sniffing for IE and use :selected pseudoselector everywhere

* Use prop("property", false), rather than removeProp("property")
* Use prop("selected", true), rather than prop("selected", "selected")