URI Rewriting

[machawk1]

From https://code.google.com/archive/p/warrick/issues/33

URI format changes by the archives have rendered the -k and uri-rewriting features inoperable. we need to develop a way -- without hardcoding -- to either automatically or easily manually change the URI strings that we need to detect to make relative.

Archive watermarks, status bars, and other archive-added features should be treated similarly.