Updated SimpleCocoaVTK to actually build against VTK git master

-Before this, the Xcode project was referring to VTK5 library names.
-Upped requirements to OS X 10.7 / Xcode 4 or better.
-Updated Instructions.rtf
-Updated Xcode project and nibs to newer format
-Updated CMAKE_MINIMUM_REQUIRED to match VTK itself
-Although it now builds, there is still a crash at runtime...

Change-Id: Idc8c2bd668ea4cff3411cde026bd26a609a00843
Merge topic 'SimpleCocoaVTK-updates' into master

cf7d187a Updated SimpleCocoaVTK to actually build against VTK git master