Automatic build command for OV

Usage:

• Configure setting and directory path in config.json file.
• run this command: "node main.js --help" for usage and

How it works?

• Spawn 2 child processes to trigger 2 build processes simultaneously, after 2 build processes are finish, trigger build "Stage" folder. Then start default services.

Library:

• bluebird: a fully featured promise library
• commander: Provide command-line interface
• del: delete file and folder
• winston: logging information to files
• cli-spinner: command-line spinner

TODO:

Kill ongoing process when 1 of simultaneously build process is failed. (user onCancel callback of Bluebird promise)