Merge pull request ampproject#1113 from Automattic/update/bump-0.7

Bump 0.7

Merge pull request ampproject#1110 from Automattic/bump/0.7-rc2

Bump 0.7-RC2 and add Piotr Delawski to props

Merge pull request ampproject#1055 from Automattic/update/0.7-changelog

Update changelog for 0.7

Merge pull request ampproject#953 from Automattic/fix/vip-review

VIP Review Changes

Bumped version to 0.7-beta1

Merge pull request ampproject#950 from Automattic/update/0.6.1

Bump 0.6.1

Bump 0.6.0

Bumped version to 0.6-rc2

Add back-compat for Customizer in WP<4.9

Update version and readme