Add RandomlyGenerated::Integer

This is mostly a proof of concept at this time.
Need to flesh this out more and add tests (or re-write using TDD).
Add RandomlyGenerated::String

This is just a proof of concept at this time.
Need to flesh this out more and add tests (or re-write using TDD).
Add rubygems-tasks, to get `rake console`

This is to follow the [Ernie Miller Rule] for gems.

[Ernie Miller Rule]: http://erniemiller.org/2014/02/05/7-lines-every-gems-rakefile-should-have/