Change "Sync-Lock Tracks" button image from chain-link to clock.

EXPERIMENTAL_LINKING -> EXPERIMENTAL_SYNC_LOCK

Restore some "border" lines in TrackInfo.


Get rid of unused DEFINE_COLOUR( clrTrackInfoSyncLockSel...).

Clean out some undocumented commented-out code. Add/remove some comments.

src/toolbars/ToolManager.cpp

@@ -584,7 +584,7 @@ void ToolManager::ReadConfig()
             bar->Create( mBotDock );
          }
 
-#ifdef EXPERIMENTAL_LINKING
+#ifdef EXPERIMENTAL_SYNC_LOCK
          // Set the width
          if( width[ ndx ] >= bar->GetSize().x )
          {