graphene.Int Scalars are not double-precision as documented

[dkleissa]

The docs currently list graphene.Int scalars as:

"Represents non-fractional signed whole numeric values. Int can represent values between -(2^53 - 1) and 2^53 - 1 since represented in JSON as double-precision floating point numbers specified by IEEE 754."

In our testing, Ints appear to be single precision, not double. Is this just a documentation issue, or something else we are missing?

[ProjectCheshire]

Fixed by #891