Lexer should pass character position to parseError

The Jison parser provides useful location information to its parseError function - the lexer currently does not provide any location information to parseError at all.

https://github.com/zaach/jison/blob/5e13d8563c306c66cc00b9fe22ff6da74617e792/lib/jison.js#L1037-L1043

While implementing https://github.com/TryGhost/GQL/issues/4 the only solution I could find to get the location of the error was by parsing it out of the error message.