Moving to top level

An additional cursor-manipulation facility that allows the user to quickly move to the top level, regardless of form depth. It is not as mature or as general as Emacs' beginning-of-defun, but it is useful.

This basic implementation has its limits, the most significant one being a reliance on canonical indentation: if the opening parens of the top-level form is not at column 0, the command blissfully misses it and goes its merry way to the preceding one.

As an organizational note, I should add that beginning-of-defun and end-of-defun are not part of the original paredit, but rather of Emacs' own LISP mode. However, the Paredit plugin seems the most relevant codebase for the command in LT, since objs/editor is mostly concerned with general utilities and CodeMirror wrapping. Let me know if you think otherwise.