ENH: Reporting OTB_GL_USE_ACCEL in otbConfigure.h so that external apps do not need to care about it

STYLE: Add new Cmake variable OTB_DATA_USE_LARGEINPUT [OFF] and OTB_DATA_LARGEINPUT_ROOT for the dierctory

COMP: Cmake correction: Update OTB_IO_UTILITIES_DEPENDENT_LIBRARIES variable and add it in th eOTBConfig.cmake.in.
Must use this variable in your TARGET_LINK_LIBRARIES() command.

ENH: Add CMake option(OTB_USE_EXTERNAL_EXPAT [OFF] ) to select or not the system lib EXPAT or the internal OTB directory.

OTB find expat lib on th esystem and try to compile a specific program. Il compilation no succeess, we decided to compile the expat on OTB/Utilities.

OTB search if the OpenThreads library exist on the platform. If NO, we compile the OpenThreads library

Modif cmakelist par rapport au Testing : OPTION(BUILD_TESTING ..) est supprimé du CMakeListst de l'OTB (doublon avec celui présent dans Dart.cmake inclue dans cmake root).
Suppression de l'option BUILDING_EXAMPLES_TESTING.

Utilisation de deux variable CMakeLists OTB_USE_JPEG2000 (modif utilisateur) et OTB_COMPILE_JPEG2000 (variable interne pour gérer la compilation)
: Modification de la variable define pour la compialtion de JPEG2000:  remplacement de ADD_DEFINITION(-DOTB_USE_JPEG2000 ) par ADD_DEFINITION(-DOTB_COMPILE_JPEG2000 )
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