Use JSON whitespace

Use JSON whitespace: _space_, _tab_, _carriage return_ and _line feed_.
Throw on any characters with a Unicode code point value of 0x1F or less.
See [[ES §7.2](http://es5.github.io/#x7.2)] and [[§15.12.1.1](http://es5.github.io/#x15.12.1.1)]