Merge branch 'ds/bundle-uri-4'

Bundle URIs part 4. * ds/bundle-uri-4: clone: unbundle the advertised bundles bundle-uri: download bundles from an advertised list bundle-uri: allow relative URLs in bundle lists strbuf: introduce strbuf_strip_file_from_path() bundle-uri: serve bundle.* keys from config bundle-uri client: add helper for testing server transport: rename got_remote_heads bundle-uri client: add boolean transfer.bundleURI setting clone: request the 'bundle-uri' command when available t: create test harness for 'bundle-uri' command protocol v2: add server-side "bundle-uri" skeleton