This mostly involved frobbing imports between realstd, realcore, and the core
being test. Some of the imports are a little counterintuitive, but it mainly
focuses around libcore's types not implementing Show while libstd's types
implement Show.
This implements all traits inside of core::num for all the primitive types,
removing all the functionality from libstd. The std modules reexport all of the
necessary items from the core modules.