reset "change" variables on tasproj load

Doing this fixes tasproj prompting for save on bk2->tasproj conversion (which makes no sense) and generally seems senseful to do; there is no point ever having a changelog or changes bool set just after loading a tasproj

src/BizHawk.Client.Common/movie/tasproj/TasMovie.IO.cs

@@ -77,6 +77,9 @@ namespace BizHawk.Client.Common
 				Session.PopupMessage("The current .tasproj is not compatible with this version of BizHawk! .tasproj features failed to load.");
 				Markers.Add(0, StartsFromSavestate ? "Savestate" : "Power on");
 			}
+
+			ChangeLog.Clear();
+			Changes = false;
 		}
 		
 		private void LoadTasprojExtras(ZipStateLoader bl)