Implement notebook display

Author: martinRenou

CMakeLists.txt

@@ -60,6 +60,7 @@ set(XFRAME_HEADERS
     ${XFRAME_INCLUDE_DIR}/xframe/xframe_expression.hpp
     ${XFRAME_INCLUDE_DIR}/xframe/xframe_trace.hpp
     ${XFRAME_INCLUDE_DIR}/xframe/xframe_utils.hpp
+    ${XFRAME_INCLUDE_DIR}/xframe/xio.hpp
     ${XFRAME_INCLUDE_DIR}/xframe/xmasked_view.hpp
     ${XFRAME_INCLUDE_DIR}/xframe/xnamed_axis.hpp
     ${XFRAME_INCLUDE_DIR}/xframe/xselecting.hpp