When dividing BigDecimal by a Float, the Float is converted to
Rational “for higher precision,” and then divides the numerator
by the denominator. However, when doing that division, `div19`
was being used which does a `floor` on the returned float. This
commit replaces the call to `div19` with `op_div`.
This commit also addresses issues with return type of the result,
which changes from version to version in Ruby.
See https://github.com/rubyspec/rubyspec/pull/220 for tests.
Use java.math.BigDecimal to compute rational and float value.
Make test applicable for 1.9/2.0 only.
A bit of housekeeping, adding whitespaces after commas, and around
Return Float when BigDecimal is divided by Float in 1.9.
Recent versions of 1.9.3 now exhibit the same behaviour as 2.0.