Line and Column Numbers on Error Messages

It just so happened that I needed stronger feedback for syntax errors for Grapnel.  So I spent a little time to update my favorite TOML parser to do the job.  As it turned out, the fix required only a few changes:

* Added line and column logic to the lexer
* Refactored parser error handling to take advantage of token.line and token.col

The bulk of this pull request contains changes to the test suite. Every token test table entry had to be updated to include the new line and column numbers.  The parser test suite was also touched to include the new error message format, which also includes the line and column number.