QMLWidget05:
-Made cube move more smoothly.
-Made cube scalable by ctrl+x-axis drag.
-Enabled cube x-y translation by shift+alt+drag operation.
-Added perspective projection(QMLWidget05_04 class).
-Added some descriptions for objects in QML.
-Modified positions of objects in QML.
-Modified view volume in QMLWidget05_03 class.
-Modified some initial values in QMLWidget05_03 class.