v2.1

This release adds automatic time formatting, aggregate rollovers, aspect ratio preservation, a formal testing framework, and closes 25 issues. For a complete list of changes, please refer to the 2.1 milestone.

We also just crossed 205,000 hits!

Thanks to @dandehavilland for major contributions to this release, and to @mikaelbr, @rfk and @t2k for their PRs.