after a reboot the arrow keys had different keycodes. lol wut? recognize both sets.
s/classes/env/ and update halp test results
keep env out of parser module
refactor Code, Block, and Method
extract make_method
use make_method
change block protocol to leave out ignored argument (the block itself); and we needn't overload __call__
attach source code to methods
visit prev/next method using pgup/pgdown