Backport mozilla#308 onto 0.6.1

Merge pull request mozilla#364 from mozilla/simplify-section-consumer

Pass through the implementation of more index map operations.

Bump to version 0.7.3

Bump to 0.7.2

Merge pull request mozilla#323 from fitzgen/bump-to-0.7.1

Bump to version 0.7.1

Merge pull request mozilla#309 from fitzgen/get-ready-for-new-release…

…-on-npm

Get ready for new release on npm

Merge pull request mozilla#290 from tromey/version-0.6.1

Release version 0.6.1

Merge pull request mozilla#287 from tromey/version-0.6.0

Release version 0.6.0

Bump to 0.5.7

Bump to 0.5.6