View panes display plugin. Note that this checkin may break a bunch of content types because I added $subtype to some content type declarations and need to go through all the content types and update the render and title functions.

Templatize all panel layouts; give each layout its own directory for cleanliness. Slight improvement to the API needed for the move to work.

Initial D6 work -- this includes only panels.module stuff. Right now the drag & drop display editor works, layout, layout settings and render works. Special features such as cache and styles may or may not work.