Remove unnecessary box-sizing properties.
Updated to Bourbon 3.2.3.
Move all dependencies back into devDependencies.

We had to move them into dependencies for Heroku buildpack quirk. Since
we’re not using Heroku anymore, we can move them back.
Ensure we don't accidentally include jQuery 2.x.
Wee re-organization in main SCSS build file.
Dropping alternative button sizes from design feedback.
H3 and H4 should be gray again (per design review).
Updated to Bourbon Neat 1.5.1.
Merge pull request #308 from DoSomething/misc-cleanup

Misc cleanup