v3.1.0

Changed

• Upgrade airtap from 0.0.6 to 0.0.7 (@ralphtheninja)
• Update .npmignore (@ralphtheninja)
• Tweak copyright year for less maintenance (@ralphtheninja)

Added

• Expose db.iterator() (@vweevers)
• Add remark tooling (@vweevers)

Removed

• Remove contributors from package.json (@ralphtheninja)
• Remove copyright headers from code (@ralphtheninja)
• Remove LevelDB and Snappy credits (@vweevers)

Fixed

• Replace remark with remark-cli (@ralphtheninja)