fast non-locale aware float format
Django's `floatformat` is a good way to format a number if you require a specific amount of decimals. It is, however, very slow. In testing each `floatformat` call took 200–250 us, which means it'll take a second to render a page that floatformats 4000 numbers. Much of the time comes from using `Decimals`. I looked at using the `cdecimal` module, and while it improved the speed, each call still clocked in at between 80 and 100 us. `fast_floatformat` is not locale aware, and doesn't look at Django settings for USE_THOUSAND_SEPARATOR, but it'll take between 1.2 and 3 us per call for ints, floats and strings, and about 12 us per call for Decimals, giving you up to 800000 floatformatted numbers per second.
- floatformat