Add mailmap to merge Alan's old usernames (#162)

I've avoided putting any of his active email addresses here for spam reasons.

Author: eric-wieser

.mailmap

@@ -0,0 +1,12 @@
+# Prevent git from showing duplicate names with commands like "git shortlog"
+# See the manpage of git-shortlog for details.
+# The syntax is:
+# Name that should be used <email that should be used> Bad name <bad email>
+#
+# You can skip Bad name if it is the same as the one that should be used, and is unique.
+#
+# This file is up-to-date if the command git log --format="%aN <%aE>" | sort -u
+# gives no duplicates.
+
+Alan Bromborsky <[email protected]> brombo <[email protected]>
+Alan Bromborsky <[email protected]> <[email protected]>