Error Messages Could Be More Helpful

[machineghost]

First off thanks for making this great library!

Second, if possible it would be great if the error messages could give more helpful info. For instance, instead of just throwing Missing element text, you've already got access to the parent element, so why not throw Missing element text for FooTag?

Small change, but would make debugging a lot easier.

Thanks.

[fxedel]

Definitely agree.