Don't override -[NSIndexPath isEqual:]

Index paths are used with other Cocoa classes, and may contain more than 2 items. The default implementation of -isEqual should already handle the 2-item case correctly.
Don't truncate index paths in -debugDescription.

If a version that displays the section and item is needed, it should probably have a unique name. Messing with NSIndexPath globally can cause unexpected results elsewhere.
Merge pull request #131 from bjhomer/pr/indexpath-isequal

Don't override -[NSIndexPath isEqual:]