Complete output chip constraints

[morganthomas]

Currently, the output chip has its local sends and receives commented out. These should be re-enabled, and in general the output chip should be checked for soundness and completeness. There should be a test in the test suite which proves an execution including a WRITE instruction, to check the functionality and provability of the output chip instruction.

[morganthomas]

Does anything need to be done here? We're not sure of the intentions of the person who wrote these local sends and receives.