Added camera sensors to robot model

Now the Scitos robot model is equipped with a video, depth and semantic camera by default. 

If you wish to start the robot without any camera provide `Scitosa5.WITHOUT_CAMERAS` in the robot's constructor (see example below). Starting the robot without any camera is useful to run MORSE in <strong>fast_mode</strong>.

If you only want to disable the depth camera, provide `Scitosa5.WITHOUT_DEPTHCAMS` in the constructor. This might be useful if you run MORSE on MacOSX, because users have reported problems when using a depth camera.

Example usage in the MORSE builder script:

* with cameras:

        robot = Scitosa5()
        # Alterntively
        # robot = Scitosa5(Scitosa5.WITH_CAMERAS)

* without cameras
                            
        robot = Scitosa5(Scitosa5.WITHOUT_CAMERAS)

* without depth cameras
        
        robot = Scitosa5(Scitosa5.WITHOUT_DEPTHCAMS)

Closes #1