Add a .mailmap file

This will make my name and e-mail address remap properly in command-line
Git tools.

.mailmap

@@ -0,0 +1,3 @@
+Faith Ekstrand <[email protected]> <[email protected]>
+Faith Ekstrand <[email protected]> <[email protected]>
+Faith Ekstrand <[email protected]> <[email protected]>