Add UndoSystem implementation and refactor UndoNode for simplicity.

cmake/packaging.cmake

@@ -3,7 +3,7 @@ include(InstallRequiredSystemLibraries)
 
 if (CMAKE_BUILD_TYPE STREQUAL "Debug")
     set(CPACK_DEBIAN_PACKAGE_DEBUG ON)
-endif()
+endif ()
 
 set(CPACK_PACKAGE_VENDOR "Shimmering Clarity")
 set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "kyle's editor")
@@ -14,11 +14,11 @@ set(CPACK_PACKAGE_VERSION_PATCH ${PROJECT_VERSION_PATCH})
 ###################
 ### DEBIANESQUE ###
 ###################
-if(${BUILD_GUI})
+if (${BUILD_GUI})
     set(CPACK_COMPONENTS_ALL gui nox)
-else()
+else ()
     set(CPACK_COMPONENTS_ALL nox)
-endif()
+endif ()
 
 set(CPACK_COMPONENTS_GROUPING ONE_PER_GROUP)
 set(CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS ON)
@@ -31,25 +31,25 @@ set(CPACK_PACKAGE_nox_DESCRIPTION ${CPACK_PACKAGE_DESCRIPTION})
 set(CPACK_PACKAGE_nox_PACKAGE_NAME "kte")
 set(CPACK_DEBIAN_nox_PACKAGE_NAME "ke")
 
-if(BUILD_GUI)
-    set(CPACK_PACKAGE_gui_PACKAGE_NAME "kte")
-    set(CPACK_DEBIAN_gui_PACKAGE_NAME "kte")
+if (BUILD_GUI)
+    set(CPACK_PACKAGE_gui_PACKAGE_NAME "kge")
+    set(CPACK_DEBIAN_gui_PACKAGE_NAME "kge")
     set(CPACK_PACKAGE_gui_DESCRIPTION_SUMMARY " graphical front-end for kyle's editor")
     set(CPACK_PACKAGE_gui_DESCRIPTION "graphical front-end for ${CPACK_PACKAGE_DESCRIPTION} ")
-endif()
+endif ()
 set(CPACK_DEBIAN_PACKAGE_SHLIBDEPS ON)
 set(CPACK_DEBIAN_PACKAGE_GENERATE_SHLIBS ON)
 
 
-if(LINUX)
+if (LINUX)
     set(CPACK_GENERATOR "DEB;STGZ;TGZ")
-elseif(APPLE)
+elseif (APPLE)
     set(CPACK_GENERATOR "productbuild;TGZ")
-elseif(MSVC OR MSYS OR MINGW)
+elseif (MSVC OR MSYS OR MINGW)
     set(CPACK_GENERATOR "NSIS;ZIP")
-else()
+else ()
     set(CPACK_GENERATOR "ZIP")
-endif()
+endif ()
 
 set(CPACK_SOURCE_GENERATOR "TGZ;ZIP ")
 set(CPACK_SOURCE_IGNORE_FILES