added original robotwar manual from internet
changed :column to :pos in metadata
added support for multi-line lexing
removed ability to distinguish between unary and binary '-' operators in lexing function
got rid of extraneous digit? function
got rid of old commented-out code
refactored to destructure head and tail in lexer
added list of commands data structure, for parser
changed name of lexing token key from token to token-str
wrote parse-token function to parse a single lexed token
wrote tests for parse-token and its helper functions
got parsing of lexed programs working