v2.0.1

Changed

• Upgrade leveldown devDependency from ^1.4.1 to ^4.0.0 (@ralphtheninja)
• Upgrade standard devDependency from ^10.0.3 to ^11.0.0 (@ralphtheninja)

Added

• Add node 9 and 10 to Travis (@ralphtheninja)
• Add UPGRADING.md (@ralphtheninja)

Removed

• Remove node 7 from Travis (@ralphtheninja)