Prior to 1.10, all numeric values where read as floats. In 1.10
numeric values are read using 0 + x, which relies on PHP type
juggling rules. As a result, float(0.0) is written as string('0'),
then read back as int(0). This fix causes the writer to retain the
the decimal for float values such that a reader can differentiate
floats from ints.
Closes#1262
cf30c2a824