tastudio: loop guid dup check.

don't remove marker 0.
update when going to frame 0.
don't check hasDuplicate against current states if branch is not current (what was it for at all?). releases Used per branch removal.

BizHawk.Client.Common/movie/tasproj/TasBranch.cs

@@ -27,11 +27,8 @@ namespace BizHawk.Client.Common
 		{
 			var currentHashes = this.Select(b => b.UniqueIdentifier.GetHashCode()).ToList();
 
-			// TODO: loop until this is unique
-			if (currentHashes.Contains(item.UniqueIdentifier.GetHashCode()))
-			{
-				item.UniqueIdentifier = Guid.NewGuid();
-			}
+			do item.UniqueIdentifier = Guid.NewGuid();
+			while (currentHashes.Contains(item.UniqueIdentifier.GetHashCode()));
 
 			base.Add(item);
 		}

BizHawk.Client.Common/movie/tasproj/TasMovieMarker.cs

@@ -218,6 +218,8 @@ namespace BizHawk.Client.Common
 			{
 				if (this[i].Frame >= startFrame)
 				{
+					if (i == 0)
+						continue;
 					_movie.ChangeLog.AddMarkerChange(null, this[i].Frame, this[i].Message);
 					RemoveAt(i);
 					deletedCount++;

BizHawk.Client.Common/movie/tasproj/TasStateManager.cs

@@ -698,8 +698,8 @@ namespace BizHawk.Client.Common
 				if (!BranchStates[frame].ContainsKey(branchHash))
 					return -2;
 				stateToMatch = BranchStates[frame][branchHash];
-				if (States.ContainsKey(frame) && States[frame] == stateToMatch)
-					return -1;
+				//if (States.ContainsKey(frame) && States[frame] == stateToMatch)
+				//	return -1;
 			}
 
 			// there's no state for that frame at all

BizHawk.Client.EmuHawk/tools/TAStudio/TAStudio.Navigation.cs

@@ -39,7 +39,7 @@ namespace BizHawk.Client.EmuHawk
 
 				MaybeFollowCursor();
 
-				return;
+				//return; seriously? well, maybe it's for some insane speedup, but it skipped updating when putting playback to frame zero.
 			}
 			else // Emulate to a future frame
 			{