always restore master track auto-icon rules when loading projects [p=…

…2802388] (#1889)

REAPER does not store master track icon in the project file. Icons on the master track might be a bug that SWS exploits(?).

Master track rules used to be applied on every project load from SWSTimeSlice::SetTrackListChange before Autocolor's ProcessExtensionLine.

b95beb0 changed the timing to run auto-coloring only once asynchronously (on the next timer tick).

Color/Autocolor.cpp

@@ -1204,7 +1204,8 @@ static bool ProcessExtensionLine(const char *line, ProjectStateContext *ctx, boo
 				GUID g;
 				stringToGuid(lp.gettoken_str(0), &g);
 				MediaTrack* tr = GuidToTrack(&g);
-				if (tr)
+				// not loading master track cache to always re-apply rules (icon isn't persisted in RPP)
+				if (tr && tr != GetMasterTrack(nullptr))
 				{
 					auto rt = g_pACTracks.Get()->insert(tr).first;
 					rt->m_col = ImportColor(lp.gettoken_int(1));