Verbosity when the rewrite structure is set
Functional tests for rewrite
Support for `wp rewrite list --match=<url>`
Support for displaying and filtering by the source of a given rewrite rule

Mostly copied from Rewrite Rules Inspector.
Drop pre-3.4 compat

See https://github.com/wp-cli/wp-cli/pull/813#discussion_r6786977
Merge pull request #813 from wp-cli/improve-rewrite

Misc improvements to `wp rewrite`