Renamed the tokens to be a little bit more identifible instead of confined to four letters.  Added RBRACK and LBRACK to the tokens so that we can finish off the lexer.
Because some of the tokens were renamed, like ENDF to EOF, it had to be updated in the scan command which checked for the ENDF token.
Added checks for keywords (ifTrue:) and LBRACK ({), and RBRACK (}).  This should complete the lexer for all elements relevant to True and False