refactored riak_core bits of the schema in here, with tests

[joedevivo]

Although the rebar.config specifies cuttlefish:develop, it will need jd-test-tools to run until basho/cuttlefish#42 is merged. If you do review this, be a dear and review that too? :)

I've refactored the riak_core bits of the schema into the riak_core project for easier testing and less duplication of schema files between the riak and riak-ee repos..

[jrwest]

missing an -ifdef(TEST)

[joedevivo]

I thought we didn't bother with -ifdef(TEST) for modules in the test dir

[jrwest]

hrm i guess its mixed, some do some dont [1] [2]

[1] https://github.com/basho/riak_core/blob/develop/test/hashtree_eqc.erl#L4
[2] https://github.com/basho/riak_core/blob/develop/test/riak_core_service_mgr_tests.erl#L23

I'd vote for having it but don't really care that much

[jrwest]

Going to go ahead w/ the +1 now since any changes are just comments and maybe an ifdef. Tests run as part of make test and pass for me. Schema looks good. I mentioned to @joedevivo elsewhere that there are some riak_core application config vars we probably want to add the to schema, but those can be added separately (we should open an issue though).

+1 merge.