#844062: Turned the normal drag and drop editor into a renderer plugin, made the IPE part of it. Also some fairly serious code reorganization.

Deprecated panels_get_panels() function. This will be eventually disappear. Use panels_get_regions() instead.

Added allowed layouts to settings form for panel pages, nodes, minis.

Some major restructuring, catching up to CTools. This is very much in process, there is a huge list of things that need to happen here still, but this may be checkpoint usable to the strong-stomached.

More tweaks to panel delegator stuff, including moving more work from the plugin to delegator.inc and displaying information about the panel display in a delegator dropdown.

Just need to get the delete button working and then go through all the contexts, relationships and arguments to make sure their forms are working.

Initial port of panels mini; still need to work on the "context" ajax stuff and convert it to the new system, but the other stuff appears to work at least a little. Also include some fixes to layouts as "id" turns out to be illegal due to Drupal setting its own id string.

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.