Updated function signatures to include $subtype as first parameter; also cleaned up repetitive copy/pasted docblocks on many render callbacks.

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.

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.

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.