Add global repaint method and make getElementData private

#### Refactor
- getElementData() is used only inside core and is therefore private from now on

#### Added
- repaint() was added to asimov.core to provide a global repaint method to fix issues with old Internet Explorer versions (8) and some native Android browser
- Setting the existing classname(s) to the element itself seem to be the only reliable approach which works across the affected browsers