- dateNF option for default date format override
- general format renders undefined/null as empty string
- ignore text elements when searching for decimal point
- bubble negative sign to the front when format starts with text
- fixes for eslint + closure
- updated frac to 1.0.6

Issues:
- fixes #10 h/t @adamgundy @SegFaultx64 @RichardCzechowski
- fixes #15 h/t @wilg
- fixes #25 h/t @dougschiller
- fixes #26 h/t @rjmcguire