grunt create-sim should not always add phet-io dependencies

[samreid]

For instance, for open source clients, we will not want to have the phet-io repos in the dependencies. That affects tasks like grunt checkout-main.

[zepumph]

This may be a similar part of discussion in #30. I feel like we need a flag in create-sim as to whether or not the sim is being create for phet or sceneryStack. This could include the change to the copyright lint rule.

[samreid]

~/.phet/build-local.json as accessed in buildLocal.js already has a section for brands, which defaults to ['adapted-from-phet']. Should we use that?

[zepumph]

Unassigning until we work on this for POSE2 (actually using the flag).