Create revisit test dataset

[kris-sigur]

A dataset needs to be created that contains the various different type of revisit records that are possible.

See further here: https://github.com/iipc/openwayback/wiki/How-OpenWayback-handles-revisit-records-in-WARC-files

This dataset would serve an immediate need to validate the handling of such records and also provide the foundation for an automated test to guard against future regressions

[PsypherPunk]

Is this being covered, at least in part, by the warc-specification project?