Added KnockoutJS data-binding support

Added KnockoutJS support by using a custom 'multiselect' binding handler.

Example:

1. Define select input
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<select class="multiSelect" data-bind="multiselect: true,options: Options, selectedOptions: SelectedOptions, optionsValue: $data" multiple="multiple"></select>

1. Initialize Bootstrap-multiselect
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$(".multiSelect").multiselect();

3 .Apply view model