IEEE 754 floating point sometimes results in values that are very small,
rather than zero. One example is 1.0 + 1.07 - 2.07, which returns
4.440892098500626e-16 instead of 0.
This change tweaks the number formatting logic so that an exponential
value with a negative exponent that is larger than the precision+1
returns 0 instead. For example: with precision 2, anything with an
exponent of -4, -5 or more would become 0. 9e-3 = 0.009 = 0.01, but 9e-4
= 0.0009 = 0.001 = 0.00. This detail is unlikely to matter since this
quirk is usually only triggered with values very close to zero.
Closes#1469
bca1604c12