v2.0.0-rc1

Changed

• Upgrade leveldown from ^3.0.0 to ^4.0.0 (@greenkeeper)
• Upgrade level-packager from ~1.2.0 to ~3.1.0 (@ralphtheninja)
• Upgrade level-js from ~2.1.6 to 3.0.0-rc1 (@ralphtheninja)
• Use proper version range for tape (@ralphtheninja)
• Homogenize README headers, add table of contents and document the api (@ralphtheninja)
• Separate tests into node and browser specific versions (@ralphtheninja)
• Import levelup integration tests from level-js (@ralphtheninja)
• Be explicit when running tests from level-packager (@ralphtheninja)

Added

• Add node 9 and 10 to Travis (@ralphtheninja)
• Add airtap for local browser testing (@ralphtheninja)
• Add standard for linting (@ralphtheninja)

Removed

• Remove node 0.12, 4, 5 and 7 from Travis (@ralphtheninja)