If you open emacs with a file (emacs file.txt), the file is switched to
before the switch-buffer hooks are set up. However, many core packages
are hooked to those switch-buffer hooks (to load when they're first
triggered). They miss the boat and don't get loaded.
These packages are now hooked onto after-find-file as well (and
immediately), which will fire when a file is opened, before or after
initialization.
Fixes#680