got wikidiff2 persistence working except for paragraph moves.

README.rst

@@ -20,6 +20,13 @@ associated tests to work.
 - 7zip
 - ffmpeg
 
+A new diff engine based on `_wikidiff2` can be used for word-persistence. Wikiq can also output the diffs between each page revision. This requires installing Wikidiff 2 on your system. On Debian or Ubuntu Linux this can be done via.
+
+``apt-get install php-wikidiff2``
+
+You may have to also run.
+``sudo phpenmod wikidiff2``.
+
 Tests
 ----
 To run tests::
@@ -30,3 +37,5 @@ TODO:
 _______________
 1. [] Output metadata about the run. What parameters were used? What versions of deltas?
 2. [] Url encoding by default
+
+.. _wikidiff2: https://www.mediawiki.org/wiki/Wikidiff2