dev-depend on grunt-peg
grunt file with 'peg' task setup
initial sgf grammar definition
generated sgf parser
try to parse the file again

(fails)
SGF: value type definition is order dependent

But really this won't work: the correct type to parse should be
determined by the property ID. For now at least parse everything as
'Text'.
sgf grammar allows whitespace between some tokens
preliminary SGF AST generation