Contribution instructions unclear

[EricTendian]

Couple issues I found while reading through CONTRIBUTING.md:

• "Use the above link to sign the CLA with your GitHub credentials." but there is no link above that points to a place to sign the contributor license agreement.
• No dev branch in this repository (mentioned a couple times).
• The instruction "Build your changes locally to ensure all tests pass:" references grunt test but the project now uses gulp.
• Roadmap link is broken (points to https://github.com/Chicago/wiki/Roadmap at the moment).

I think these need to be addressed before anyone can successfully submit a pull request.

[tomschenkjr]

The CLA should be enforced by CLA Hub. But it's still valid. I've updated the doc to remove reference to signature since it's integrated into the pull request workflow.

We've paused on a grand roadmap, so will point to the other planning documentation (which has similar content).

Changed the grunt to gulp.

Developed a dev branch based on all of these changes.

[EricTendian]

@tomschenkjr thanks! The changes you made clear that up.