Remaking the GridEditor Step 1 of 5

the "editor" is basically housed within a display object called
edit_wrapper. onEdit, the edit wrapper centers the display. Then, the
editor generates proxies for every sub-module so that we can track
changes to the proxies without having to worry about MouseEvent or
TouchEvent making a mess on the actual sub-modules.

This commit completes the proxy generation and display.
Next: listen for reordering
Next: add other grid properties as a "form"
Next: add "new asset" search
Next: add "new asset" ingest, and add result back to current grid
Next: add a delete button on images
Next: add a "resize" option to sub-assets