rand(::MemorizingRNG, ::Type{Int}) doesn't work

[zsunberg]

Some methods of rand don't work for the MemorizingRNG. This is because I didn't take the time to reverse - engineer all the MersenneTwister code that I needed to.

It's not clear how crucial this is because it seems like people would rarely actually want to use rand(..., Int). The most common usages that I could think of (see test/memorizing_rng.jl) seem to work fine, so maybe this is not a big issue.