Fixed some rendering and added variables to cook() unit display.

Fixed bug in f8unit which would lead to displaying .00000000000001 as 10ms.

Out of unit bounds numbers are now rendered in scientific notation. No good
options here, anything else is just about guaranteed to blow the formatting.

0.0 is now rendered without decimal places.

Added temporary renderer for data in ppm.

Added some missing variables, including ppms, to the cook() handler. This can't
be completed until the Great Unit Hunt is complete.