Add the autorevision tool to Wesnoth.

This version used is 1.4 and is copied from [1].

[1] http://www.catb.org/esr/autorevision/


git-svn-id: http://svn.gna.org/svn/wesnoth/trunk@56497 75b3775d-3801-0410-9e12-e2e43121521d