Make sure CLI interface works

[jtremback]

CLI is started in ./offchain/cli.js, but a lot has changed in ./offchain/logic.js since the last time the CLI worked. There are probably some updates that need to be done.

I'm not sure if the CLI should be tested, since those tests will likely be pretty redundant with the tests in ./offchain/logic.js, as well as the contract tests in ./test/, but we may want to make a shell script that at least runs through the most common commands.