Add noun.hoon mark to /mar
Add noun.hoon mark to /mar

Fixes an issue where trivial moves to ++poke-noun app arms across ships
wouldn't resolve, and ++coup in those apps would throw away the stack
trace.

See this Fora post:
<http://urbit.org/fora/posts/~2017.5.30..04.45.41..dbd2~/>

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