Handle name conflict for --version option

[draperunner]

Summary:

Fixes #711

The global --version option wouldn't print anything. That's because the name version conflicts with the built-in commander method commander.version(). Therefore, when calling commander.version, it wouldn't understand that it should use our --version option.

Here's an issue on commander that explains the same issue: tj/commander.js#1020

I have fixed this by checking if the raw arguments contain the --version argument. Even though sub-commands like init has a different --version parameter, this check is safe because of the existing check on commander.args.length === 0. The global --version option will only be used if no sub-command is used.

Test Plan:

Before applying the changes, I ran node packages/cli --version and saw that it printed nothing.
After applying the changes, I ran the same command and saw that it returned the version stated in package.json.