Bindable booleans

Prior to this release, if you were to attempt to bind a boolean value somewhere in the DOM, a 0 or a 1 would be used as the value, which doesn't seem helpful in any way.

This release allows boolean values to behave slightly differently. Now, the boolean is used to define whether the bind value's key should be output to the element.

This is useful when a flag is required to be output to the DOM. For example, adding a class to an element when a navigation menu is "selected" or a to do item is "completed".

This technique can be used to bind a predefined value to an element only when the bind key is true. When a false value is bound, nothing will be bound to the DOM.

Example adding the "open" class to a <menu> element that already contains classes:

<menu class="main-menu positive" data-bind:class="open">
	...
</menu>

$document->querySelector("menu")->bindKeyValue("open", true);