ArgumentParser cleanup

Author: arturcic

src/GitVersionCore.Tests/Mocks/MockRepository.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using LibGit2Sharp;
 
+using Index = LibGit2Sharp.Index;
 namespace GitVersionCore.Tests.Mocks
 {
     public class MockRepository : IRepository
@@ -196,7 +197,7 @@ public void RevParse(string revision, out Reference reference, out GitObject obj
 
         public Branch Head { get; set; }
         public LibGit2Sharp.Configuration Config { get; set; }
-        public LibGit2Sharp.Index Index { get; set; }
+        public Index Index { get; set; }
         public ReferenceCollection Refs { get; set; }
 
         public IQueryableCommitLog Commits