No context for unclosed element errors

[hurrymaplelad]

Given unclosed.cjsx:

1 <div>
2  <div>
3 </div>

Running

$ cjsx unclosed.cjsx

Yields

SyntaxError: Unexpected end of input: unclosed CJSX_EL

With no line numbers.

For comparison, the latest Babel-powered jsx yields:

Unterminated JSX contents (3:6)
  1 | <div>
  2 |   <div>
> 3 | </div>
    |       ^

Probably related to #28