Add option to disabling clearing of terminal console

[a-morales]

Following the guide for integrating with a node backend, I found it a bit inconvenient having the start script clearing the console every time a file was saved when running everything through foreman.

This just adds the option to pass in a --verbose(not sure if this is the right flag name) option to the start script that won't clear the console. I've read the contributing guideline, and maybe this should be an option that is enabled by default whenever proxy is defined in package.json.

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla - and if you have received this in error or have any questions, please drop us a line at cla@fb.com. Thanks!

If you are contributing on behalf of someone else (eg your employer): the individual CLA is not sufficient - use https://developers.facebook.com/opensource/cla?type=company instead. Contact cla@fb.com if you have any questions.

[gaearon]

Is this related to #1032? Does #1032 already solve this?

[a-morales]

@gaearon This is related to #1032, and I just gave this a try on the master branch and it works. I'll close the PR.

[gaearon]

Great! We’ll try to get it out within a week or two.