pass actual precision and notation to the format function

what we were doing was keeping 2 significant digits which is not the same
as keeping decimal precision.
From http://mathjs.org/docs/reference/functions/format.html
Old Code: math.format(21385, 2);                       // returns '21000'
New Code: math.format(2.3, {notation: 'fixed', precision: 2});  // returns '2.30'