CXX 14 standard forced

CMakeLists.txt

 	VERSION  "${MERLIN_VERSION_NOQUOTES}"
 	SOVERSION "${MERLIN_VERSION_MAJOR}.${MERLIN_VERSION_MINOR}"
 	PROJECT_LABEL "MERLIN ${LABEL_SUFFIX}"
+	CXX_STANDARD 14
+    CXX_STANDARD_REQUIRED ON
 )
 
 # Linking