Bring base grunt version up-to-date, retaining nopt version bump.

Merged origin/master retaining nopt version 2.1.1.

nopt 2.2.1 adds some new features, but should be compatible with our usage.
[Compare 2.1.1 to 2.2.1](https://github.com/npm/nopt/compare/v2.1.1...v2.2.1).

3.0.0 removes the implicit conversion of numerical arguments, so if 2.2.1 is compatible, 3.0.0 is likely compatible as well.
[Compare 2.2.1 to 3.0.0](https://github.com/npm/nopt/compare/v2.2.1...v3.0.0).