New rendering pipeline

I think, it's ready for prime time :wink:
There are no tests yet, maybe we should add at least some until thursday.

The Tanzmaus-Image (http://de.selfhtml.org/html/grafiken/anzeige/img.htm) is still not displayed correctly - this seems to be unrelated to the new pipeline, and I'm not sure, what the problem is in detail. 
(It probably has to do with embedding submorphs in the TextMorph and their positioning: BitBltDisplayScanner>>placeEmbeddedObject:)
If problems with displaying images occur more frequently, we should make a bug/user story out of it, but I've not seen any other websites with this problem yet.