feature: add automatic compositor engine detection
feature: add automatic compositor engine detection

this takes care of the previously-required E_WL_FORCE autodetection. E_WL_FORCE behavior unchanged

FlorentRevest/Enlightenment,rvandegrift/e,tasn/enlightenment,FlorentRevest/Enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,tasn/enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment