Issue #25 Undo/Redo LineEdit

CHANGELOG.md

forms/HLine.png

forms/Ressource.qrc

forms/mainwindow.ui

src/GraphicView.cpp

src/GraphicView.h

src/UndoFramework/lineaction.cpp

src/UndoFramework/lineaction.h

src/datamanager.cpp

src/mainWindow.cpp