Support Rational, Int32, Int64, etc.

[mchaver]

[smurphy8]

@mchaver progress?

[mchaver]

This needs to be finished first. The annoying part is we have to make our own version of the Js.Json.t type in order to support parse int64 and larger in ways that don't break JavaScript. I tried to get it into BuckleScript, but they want to wait until int64 and up get supported in JavaScript. It is something that is supposed to happen in the future, but I don't think it is that quick.
plow-technologies/rescript-aeson#7

[smurphy8]

Geesh, okay well we can just keep our own tracking of it for now.