Add more information in TokType

Should add more information in [lexer::TokType](https://github.com/onehr/crust/blob/dba8091df71d7b3abd445dab726ea93dd722aaac/src/lexer.rs#L2), it's useful to track the token position in file when the compiler fails to compile the source code, I think file name, line number, character position should be enough. And should print them in a more elegent way in parser error message.