KNOWN_ISSUES

- Dividing by zero doesn't throw an exception in objc, it fails with EXC_ARITHMETIC
- NullPointerException and ClassCastException are not reliable, as they are emulated by j2objc
- Empty regular expressions throw an exception
- pr-str a date have a bad Timezone format: https://code.google.com/p/j2objc/issues/detail?id=321