flag to not open a browser

[stephenmathieson]

e.g. if you just want to create a server/rebuild/etc.

in the vm:

somebody app (xxx) $ node_modules/.bin/duo-test --build build/tests.js --port 3000 browser

  Error: Command failed: /bin/sh -c google chrome "http://localhost:3000/test/"
/bin/sh: 1: google: not found

    at ChildProcess.exithandler (child_process.js:203:12)
    at emitTwo (events.js:87:13)
    at ChildProcess.emit (events.js:172:7)
    at maybeClose (internal/child_process.js:818:16)
    at Socket.<anonymous> (internal/child_process.js:319:11)
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at Pipe._onclose (net.js:469:12)

somebody app (xxx) $