Make StashCollection.Remove() take an index (int) param

I think we can safely avoid forcing the client to pass us the index using a "stash@{n}" pattern.

Author: yorah

LibGit2Sharp.Tests/StashFixture.cs

@@ -64,7 +64,7 @@ public void CanAddAndRemoveStash()
                 Assert.Equal(repo.Lookup<Commit>("stash@{1}").Sha, stash.Target.Sha);
 
                 //Remove one stash
-                repo.Stashes.Remove("stash@{0}");
+                repo.Stashes.Remove(0);
                 Assert.Equal(1, repo.Stashes.Count());
                 Stash newTopStash = repo.Stashes.First();
                 Assert.Equal("stash@{0}", newTopStash.CanonicalName);
@@ -197,16 +197,14 @@ public void CanStashIgnoredFiles()
         }
 
         [Theory]
-        [InlineData("stah@{0}")]
-        [InlineData("stash@{0")]
-        [InlineData("stash@{fake}")]
-        [InlineData("dummy")]
-        public void RemovingStashWithBadParamShouldThrow(string stashRefLog)
+        [InlineData(-1)]
+        [InlineData(-42)]
+        public void RemovingStashWithBadParamShouldThrow(int badIndex)
         {
             TemporaryCloneOfTestRepo path = BuildTemporaryCloneOfTestRepo(StandardTestRepoWorkingDirPath);
             using (var repo = new Repository(path.RepositoryPath))
             {
-                Assert.Throws<ArgumentException>(() => repo.Stashes.Remove(stashRefLog));
+                Assert.Throws<ArgumentException>(() => repo.Stashes.Remove(badIndex));
             }
         }
     }

LibGit2Sharp/StashCollection.cs

@@ -35,6 +35,9 @@ internal StashCollection(Repository repo)
 
         /// <summary>
         ///   Returns an enumerator that iterates through the collection.
+        ///   <para>
+        ///     The enumerator returns the stashes by descending order (last stash is returned first).
+        ///   </para>
         /// </summary>
         /// <returns>An <see cref = "IEnumerator{T}" /> object that can be used to iterate through the collection.</returns>
         public IEnumerator<Stash> GetEnumerator()
@@ -78,21 +81,36 @@ public virtual Stash Add(Signature stasher, string message = null, StashOptions
             return new Stash(repo, oid, 0);
         }
 
+        /// <summary>
+        ///   Remove a single stashed state from the stash list.
+        /// </summary>
+        /// <param name = "index">The index of the stash to remove (0 being the most recent one).</param>
+        public virtual void Remove(int index)
+        {
+            if (index < 0)
+            {
+                throw new ArgumentException("The passed index must be a positive integer.", "index");
+            }
+
+            Proxy.git_stash_drop(repo.Handle, index);
+        }
+
         /// <summary>
         ///   Remove a single stashed state from the stash list.
         /// </summary>
         /// <param name = "stashRefLog">The log reference of the stash to delete. Pattern is "stash@{i}" where i is the index of the stash to remove</param>
+        [Obsolete("This method will be removed in the next release. Please use Repository.Stashes.Remove(int) instead.")]
         public virtual void Remove(string stashRefLog)
         {
             Ensure.ArgumentNotNullOrEmptyString(stashRefLog, "stashRefLog");
 
             int index;
-            if(!TryExtractStashIndexFromRefLog(stashRefLog, out index) || index < 0)
+            if (!TryExtractStashIndexFromRefLog(stashRefLog, out index) || index < 0)
             {
                 throw new ArgumentException("must be a valid stash log reference. Pattern is 'stash@{i}' where 'i' is an integer", "stashRefLog");
             }
 
-            Proxy.git_stash_drop(repo.Handle, index);
+            Remove(index);
         }
 
         private static bool TryExtractStashIndexFromRefLog(string stashRefLog, out int index)