Remove Support for Deprecations, Preparing for v1.0

* The old Check#call method has been deprecated since nearly the beginning. The v1.0 release seems a good a time as any to finally drop support for it.
* The OKComputer namespace isn't as old, but raised an exception if it was used in any apps which upgraded to v0.7.0. Anyone who upgraded will have had to have updated their apps by now.