Allow delimc to be used without use/refer

I was taking a look at this library to talk about in the chapter of my macros book on control flow - cool stuff!

I added a new test ns that pulls over a bunch of the tests from `delimc.test.core` to verify things work without referring them. It's very non-scientific; I just pulled everything over & then deleted the ones that seemed obviously redundant once I got them all passing. Feel free to tell me to delete more of them.

Let me know if you want to see any changes. Thanks!