Add stacktrace to ParseError

Fixes #854. Also clean up the parse error test a little, while adding a .stack check.
That is very strange. Are you on Windows? Do you mind telling me what the error is exactly? By both http://msdn.microsoft.com/en-us/library/ie/hh699850(v=vs.94).aspx and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/Stack the stack property should be supported down to IE10.

And could you also check that if you instantiate a `new Error()` in the console, that you can read the stack property off of it?