GitRepository: Add an "all branches" option in branches list

This is probably the most common non-branch GitX option, so
let's add it by default

PBGitRepository.m

@@ -231,6 +231,9 @@ static NSString* gitPath;
 	}
 
 	self.refs = refs;
+
+	// Add an "All branches" option in the branches list
+	[self addBranch:[PBGitRevSpecifier allBranchesRevSpec]];
 	return ret;
 }