- move option() to main CMakeLists
- add ImportQt4.cmake and call it from main CMakeLists, before ImportGettext
- add INCLUDE(CheckCXXSourceRuns) in main CMakeLists
- use CHECK_CXX_SOURCE_RUNS instead of CHECK_CXX_SOURCE_RUNS_ARGS (need to pass the code as a variable instead of only a filename)
- simply include <QtGui> in the test

BUG:deactivate gettext by default and test possible QT/Gettext conflict in the cmake cofiguration(bug 419)