Add opam package for stdlib + various fixes

This adds an opam package refinedrust-stdlib for the stdlib. Also, this fixes some things around the rr::context annotation, adds more later credits, and adds the static_has_refinement assertion to make timeless statements about refinements of statics.

case_studies/tests/src/lib.rs

@@ -13,3 +13,5 @@ mod vec_client;
 mod mixed;
 mod closures;
 mod references;
+//
+//mod option;