credits: update contributors list

Change-Id: I0c9dd13901c82319bf3bb21bf91117d336376799
Tuleap: #134

Credits.rtf

-{\rtf1\ansi\ansicpg1252\cocoartf1265\cocoasubrtf210
+{\rtf1\ansi\ansicpg1252\cocoartf1348\cocoasubrtf170
 {\fonttbl\f0\fswiss\fcharset0 Helvetica;}
 {\colortbl;\red255\green255\blue255;}
-\margl1440\margr1440\vieww9000\viewh8400\viewkind0
+\paperw12240\paperh15840\margl1440\margr1440\vieww9000\viewh8400\viewkind0
 \pard\tx566\tx1133\tx1700\tx2267\tx2834\tx3401\tx3968\tx4535\tx5102\tx5669\tx6236\tx6803\pardirnatural\qc
 
 \f0\i\fs24 \cf0 \
@@ -20,6 +20,9 @@ Emmanuel Lepage-Vall\'e9e\
 Guillaume Roguez\
 Marianne Forget\
 Stepan Salenikovich\
+Julien Grossholtz\
+Simon D\'e9saulniers\
+Nicolas J\'e4ger\
 \
 Based on SFLphone's project\
-}
+}
\ No newline at end of file