[CMakeList] set c++11 by default, required for serialization number macro

CMakeLists.txt

@@ -25,6 +25,7 @@ INCLUDE(cmake/python.cmake)
 # Project definition
 COMPUTE_PROJECT_ARGS(PROJECT_ARGS LANGUAGES CXX)
 PROJECT(${PROJECT_NAME} ${PROJECT_ARGS})
+SET(CMAKE_CXX_STANDARD 11)
 
 # Project dependencies
 ADD_PROJECT_DEPENDENCY(Eigen3 REQUIRED PKG_CONFIG_REQUIRES eigen3)