COMP: Ajout des options en tete des CMakeLists.txt pour le warning CMP0003

CMakeLists.txt

 # This is the root OTB CMakeLists file.
 # $Id$
 #
+CMAKE_MINIMUM_REQUIRED(VERSION 2.4)
+IF(COMMAND CMAKE_POLICY)
+  CMAKE_POLICY(SET CMP0003 NEW)
+ENDIF(COMMAND CMAKE_POLICY)
 
 PROJECT(OTB)