Bugfix?: this seems to fix the "malloc refcount underflow" errors that seem to happen frequently when utilizing the QL panel from the source files outline view. Not entirely sure why though.

Author: andreberg

PBGitHistoryController.h

@@ -27,7 +27,7 @@
 	NSArray *currentFileBrowserSelectionPath;
 	IBOutlet NSTableView* commitList;
 	IBOutlet PBCollapsibleSplitView *historySplitView;
-    QLPreviewPanel* previewPanel;
+    __weak QLPreviewPanel* previewPanel;
 
 	IBOutlet PBGitGradientBarView *upperToolbarView;
 	IBOutlet NSButton *mergeButton;