[!!!][TASK] Refactoring

* Changes order of rwd-objects iteration to fix various edge cases because of nested objects
* Reruns element queries after rwd-objects code
* Adapts unit tests accordingly
* Major changes to "rwd-object-halign"
* Restricts functionality of "rwd-object-valign-middle"
* Major changes to "rwd-object-columns"
* Minor changes to "rwd-object-halign"
* Adds error callback to function "waitForImagesToLoad"
* Adds customizable loading opacity to improve usability and the perception of the frontend performance
* Demo adjustments
* Cleanup

Resolves #11