Unbinds Event Listeners now correct

The directive uses now only one resize-event-listener and can unbind all the elements with the directive when necessary.

Now with NPM Package, .min

Now with NPM package, a minified lib-file and the usage as globally defined directive is optional.

Bootstrap 4, 3 and own breakpoints supported

This release supports the usage of the breakpoints given by Bootstrap 4 and alternative by bootstrap 3. Own breakpoints can be defined and used as well. Elements can be hidden or displayed accourding to the values given to the directive.
Todo: Get Webpacker ready
Todo: Add optional classes instead of only changing the display attribute