Better export to PowerPoint (#1491)

Currently I'm using "copy as metafile" to export diagrams to PowerPoint. In PowerPoint, I'd like to animate (fade in / fade out) parts of my diagram, so that it its easier to understand (example: show first part of diagram, explain it, fade in second part of diagram, ...).

When I ungroup the diagram in PowerPoint (which converts it to a Drawing object where individual parts can be animated), every text and line in the new graphics object is a single object. There is no single "component" object that I could animate, just the individual parts of the component. This makes working with the graphic too difficult for larger diagrams.

It would be great if there was a better export to PowerPoint, where I can easily animate individual components, classes and other diagram objects.