Rename postreview.py to reviewtool.py, and modify it to take additionally an action to perform. Add a stub to implicitly take the new 'post' action. Modify setup.py so that the post-review wrapper will call this stub.
    
This will permit adding other actions which can take advantage of the general functionality in what is now reviewtool.py (e.g. finding the server, logging in) without needing to duplicate this code elsewhere.

(Further rationale: I intend to follow this with an addition to reviewtool.py to add a 'submit' action, which will take a request ID and change its status to 'submitted'.)