Add git mailmap file to canonize committer names

Without rewriting the complete commit history, we cannot adjust
the committer names or emails. Luckily git allows mapping committer
names and email via the .mailmap file in the repo.

Most visible difference is when using "git shortlog -sne"

diff --git a/.mailmap b/.mailmap
new file mode 100644 (file)
index 0000000..e0f587f
--- /dev/null
+++ b/.mailmap
@@ -0,0 +1,6 @@
+PatR <rankin@nethack.org>              nethack.rankin <nethack.rankin>
+nhmall <mjnh@persona.ca>               nethack.allison <nethack.allison>
+keni <keni@his.com>                    keni <keni>
+David Cohrs <davecohrs@gmail.com>      cohrs <cohrs>
+Derek S. Ray <derekray@gmail.com>      Derek <derekray@gmail.com>
+Alex Kompel <barbos+nethack@gmail.com> Alex Kompel <barbos+droidzebra@gmail.com>