Fix AUTHORS.txt, remove the various duplicate entries - follow-up to 2ca5fbf

Author: jzaefferer

AUTHORS.txt

@@ -212,19 +212,15 @@ John Chen <zhang.z.chen@intel.com>
 Dale Kocian <dale.kocian@gmail.com>
 Mike Sherov <mike.sherov@gmail.com>
 Andrew Couch <andy@couchand.com>
-Andrew Couch <acouch@bluewolf.com>
 Marc-Andre Lafortune <github@marc-andre.ca>
 Nate Eagle <nate.eagle@teamaol.com>
 David Souther <davidsouther@gmail.com>
 Mathias Stenbom <mathias@stenbom.com>
-elisy <ebishkek@yandex.ru>
-Avinash R <nashpapa@gmail.com>
 Sergey Kartashov <ebishkek@yandex.ru>
-Ethan Romba <ethan.romba@parivedasolutions.com>
+Avinash R <nashpapa@gmail.com>
 Cory Gackenheimer <cory.gack@gmail.com>
 Ethan Romba <ethanromba@gmail.com>
 Juan Pablo Kaniefsky <jpkaniefsky@gmail.com>
-mathias.stenbom <mathias@stenbom.com>
 Roman Salnikov <bardt.dz@gmail.com>
 Anika Henke <anika@selfthinker.org>
 Samuel Bovée <samycookie2000@yahoo.fr>