Adds filename to JSXTransform error messages

Adds the filename to JSXTransform error message, making it easier to debug JSX syntax errors.
Fixes #393 and Fixes #394
This is how the error message look like:

Firefox
![Firefox Error Message](https://f.cloud.github.com/assets/28530/1817112/fbee7d22-6f71-11e3-8402-3efa666dc07f.png)

Chrome
![Chrome Error Message](https://f.cloud.github.com/assets/28530/1817111/f44019a0-6f71-11e3-963e-41be17fc2f86.png)