exportPC Export a point cloud.
  ------------------------------------------------------------------------------
  DESCRIPTION/NOTES
  * With this method a point cloud which was previously added to the globalICP
    object, can be written to a file. Usually this is performed after the ICP
    run.
  * This method is a wrapper for the method 'export' of the 'pointCloud'
    class. Thus, call 'help pointCloud.export' for the parameter description.
  ------------------------------------------------------------------------------
  INPUT
  1 [i]
    Index of point cloud to load.
  2 [...]
    Parameters from the method 'export' of the 'pointCloud' class (see above).
  ------------------------------------------------------------------------------
  EXAMPLES
  Call 'help globalICP.globalICP' for a minimal working example, which also 
  includes this method.
  ------------------------------------------------------------------------------
  philipp.glira@gmail.com
  ------------------------------------------------------------------------------