-Removing deprecated `==` calls
-Added a bunch of package-related notes to README
-Minor code cleanup of cl-notebook.lisp
-Broke out a bunch of notebook-specific methods into model.lisp
-Each notebook now tracks its namespace (still need to finalize this; they all still evaluate into :cl-notebook)
-Added copious notes about packages
-Added ASD metadata in cl-notebook.asd
-Fixed dom-replace bug that was resulting in no cell transposing/jumping after a cell-type change