Hide dot-files by default in dired-mode

Use M-o to toggle this behavior.
Refactor H and L bindings, which move to the first or last file in the buffer.
Switch to dvorak in 'after-change-major-mode-hook

This hook runs in every new buffer created in non-fundamental mode.
Remove binding of "RET" to newline-and-indent

Interferes with things like the cider repl.
I don't even remember why it was in the first commit...