Fix for VTK6.2 issue.

 A fix for the issue is with the objective c file vtkCocoaInteractorFix.mm which was added on the 8th of Feb in commit 5dc17f5 when used with VTK6.2. The error given is

No member named 'GetCocoaServer' in 'cv::viz::vtkCocoaRenderWindowInteractorFix'

This is because GetCocoaServer has been moved from vtkCocoaRenderWindowInteractor to vtkCocoaRenderWindow in VTK 6.2. This alteration to VTK happened almost a year ago according to the gitHub commit a3e9fc9.