Flesh out the status delta.
Abstract out the string array creation.
Remove status API from GTRepository.h/m
Sketch status API in a category.
Re-implement status enumeration.

This time we use our GTStatusDelta objects.
Fix ARC complaint.
Xcode project updates.
NSArray+Pathspec -> NSArray+StringArray

It was never meant for just pathspecs so that name didn't really make
any sense at all.

This also makes the method slightly more resilient to arrays with more
than just strings in them. Generics in Objective C would sure be nice!
Unnecessary double import --;
Import GTRepository.h rather than all of ObjGit.
Update catch-all header.