Update AUTHORS and import .mailmap.

I've been using this .mailmap file in order to update the AUTHORS with
`rake authors`.

.mailmap

@@ -0,0 +1,10 @@
+Blake Mizerany <blake.mizerany@gmail.com>
+Lawrence Leonard Gilbert <larry@l2g.to>
+<larry@l2g.to> <larry@L2G.to>
+Marc-André Cournoyer <macournoyer@gmail.com>
+Matthew Manning <matt.manning@gmail.com>
+Nicholas Wieland <nicholas.wieland@gmail.com>
+Rafael Ssouza <rafael.ssouza@gmail.com>
+Richard Schneeman <richard.schneeman@gmail.com>
+Rick Olson <technoweenie@gmail.com>
+T. Watanabe <wtnabe@wt-srv.watanabe>

AUTHORS

@@ -7,6 +7,7 @@ Adrian Rangel
 Alex Tomlins
 Aman Gupta
 Andy Brody
+Avi Deitcher
 Blake Mizerany
 Brad Ediger
 Braintree
@@ -38,10 +39,12 @@ Harm Aarts
 Hiro Asari
 Hugh McGowan
 Ian Warshak
+Igor Zubkov
 Ivan Makfinsky
 JH. Chabran
 James Edward Gray II
 Jari Bakken
+Jeff Pereira
 Jeff Remer
 Jeffrey Hardy
 Jeremy Kemper
@@ -59,12 +62,14 @@ Keith Rarick
 Kenichi Kamiya
 Kevin Read
 Kosuke Asami
+Kyle Meyer
 Kyle VanderBeek
 Lars Gierth
 Lawrence Leonard Gilbert
 Lee Jarvis
 Lennon Day-Reynolds
 Lin Jen-Shin
+Magne Matre Gåsland
 Marc-André Cournoyer
 Marius Butuc
 Matthew Manning
@@ -77,6 +82,7 @@ Nicholas Wieland
 Nick Hammond
 Nick Plante
 Niko Dittmann
+Nikolay Shebanov
 Oscar Del Ben
 Pablo Astigarraga
 Paul Dlug
@@ -85,9 +91,11 @@ Pedro Chambino
 Philip Corliss
 Pierre-Louis Gottfrois
 Rafael Ssouza
+Richard Schneeman
 Rick Olson
 Robert Eanes
 Rodrigo Panachi
+Sam Norbury
 Samuel Cochran
 Syl Turner
 T. Watanabe