Update Babel Integrations

[sibiraj-s]

After Babel 7 is released few integrations were updated sooner and few are not. The two more commonly used packages grunt-babel and babebily weren't updated.

Those modules seems 100% compatible with babel7 but still in beta. Just a release is needed. No major changes required

To help release process, I created few PR's which may assist the release.

• Babel 7: Update babel devDependencies to stable version + drop nodejs 4 grunt-babel#93
• Update to Babel 7 stable + update devdependencies babelify#273

and respective issues for that.

• Babel 7 Stable Version Released grunt-babel#94
• Babel 7 Stable Released babelify#274

[babel-bot]

Hey @sibiraj-s! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
community that typically always has someone willing to help. You can sign-up here
for an invite.

[xtuc]

Since issues are already tracked on their own repos, i'm going to close this.