laughinghan/mathquill — pull request #106 by laughinghan (2012-07-23 05:47:52+00:00)
Title: Refactor directions

`.prev`, `.next`, `.first`, `.last`, `.firstChild`, `.lastChild` ⇒ `[L]`, `[R]`, `.ends[L]`, `.ends[R]`, `.ch[L]`, `.ch[R]`, respectively.