Provide better error information to users

As a user I want to get clear error messages that provide useful information on how to correct the error situation or how to recover from it. Basically "what did I do wrong?". Today Qt 3D Studio is not very good in reporting errors to the user. We have a lot of asserts that crash on debug builds only which is very bad way of handling these "errors". Either something is an error always (e.g. leaving Action item with [Unknown Event] selected) or it's not an error that needs to be bothered about.