Updated SimpleCocoaVTK example to work better on modern OS X

- removed hardcoded settings for SDK and deployment
- fixed one file reference in the Xcode project
- also fixed indentation and whitespace

Change-Id: Ib503d0fb5a59a8eec0ed98cc6026b645ea3a95ef
Merge topic 'SimpleCocoaVTKUpdates' into master

0636f23c Updated SimpleCocoaVTK example to work better on modern OS X