RFC-13: MCS: Improve constraints on grant via reply

I have posted a new RFC. It proposes a change to the semantics of reply invocations in the MCS kernel. If accepted, the ability to grant capabilities when replying would be controlled primarily by endpoint capability grant rights, rather than reply object capability grant rights:

MCS: Improve constraints on grant via reply

The RFC proposes two alternatives, implemented in pull requests:

If you have any feedback, please comment on the JIRA RFC, or one of the pull requests.

Thanks!
Matt