Move more things out of check.clj

Overhaul dependency management. See ns-deps-utils
[maven-release-plugin] prepare release core.typed-0.2.49
[maven-release-plugin] prepare for next development iteration
Add requires corresponding to imports.
Fix CTYP-144. Find correct expected types for protocol method implementations.
[maven-release-plugin] prepare release core.typed-0.2.50
[maven-release-plugin] prepare for next development iteration