add .mailmap to fix authors for git-shortlog

.mailmap

@@ -0,0 +1,16 @@
+#
+# This list is used by git-shortlog to fix a few botched name translations
+# in the git archive, either because the author's full name was messed up
+# and/or not always written the same way, making contributions from the
+# same person appearing not to be so.
+#
+
+Alexandre Fayolle <[email protected]>
+Alexandre Fayolle <[email protected]> <[email protected]>
+Alex Comba <[email protected]>
+Jacques-Etienne Baudoux <[email protected]>
+Joël Grand-Guillaume <[email protected]>
+Lorenzo Battistini <[email protected]>
+Nicolas Bessi <[email protected]>
+Romain Deheele <[email protected]>
+Sébastien Beau <[email protected]>