Change API / Rename binding

Maybe we can change the API for additional backwards compatibility:

    <select data-bind="cap3Options: myOptionsArray, value: myValueObservable"></select>

Consequences:
 - The binding has to be renamed, e.g. 'cap3Options'
 - The binding could be included by overwriting the original options binding without the need of changing any other code.
 - Minimum supported knockout version is 2.3.0 instead of 3.0.0