added MoveCamera but isn't working well

updated about text,

QtMeshViewer/Resources/about.txt

@@ -4,9 +4,22 @@ source code: https://git.rwth-aachen.de/carstenf/OpenGL/tree/master/QtMeshViewer
 
 ===============================================================
 Controll:
+
+Free Camera: static view position and you rotate and move the object
 left mouse - rotate
 right mouse - move
 scroll - zoom
+
+Orbit Camera: static object and you move around it like a satalite
+left mouse - rotate
+scroll - zoom
+
+Move Camera: static object and you can walk through the scene
+w/s - forward/backward
+a/d - left/right
+left mouse - look around
+
+General:
 space - reset view
 L - set light to current position
 esc - close