Fixed the "Discover" page to draw lines for rebased versions.

Added preliminary support for file diffs on the "Edit" page.
It needs layout / CSS cleanup but it works.

Added <<<ArchiveVersion>>> macro to print the 16 digit hex version
of the current archive.

Added <<<ArchiveUri>>> macro to print a link to the archive SSK
that the current wiki version was loaded from.

These macros where added so that people viewing dumped wiki
freesites can tell which version / uri the wiki was
dumped from.

Release notes for previous version:
USK@kRM~jJVREwnN2qnA8R0Vt8HmpfRzBZ0j4rHC2cQ-0hw,2xcoQVdQLyqfTpF2DpkdUIbHFCeL4W~2X1phUYymnhM,AQACAAE/jfniki_releases/2/