GitWindowController: Store multiple views

This keeps the subviews in memory, which means that switching views will
be faster if a view has already been opened. This also allows you to type
a commit message, switch to the history view, and then switch back to
continue typing.

PBGitWindowController.h

@@ -9,11 +9,16 @@
 #import <Cocoa/Cocoa.h>
 #import "PBGitRepository.h"
 
+@class PBViewController;
 @interface PBGitWindowController : NSWindowController {
 	__weak PBGitRepository* repository;
 	int selectedViewIndex;
 	IBOutlet NSView* contentView;
-	NSViewController* viewController;
+
+	PBViewController *historyViewController;
+	PBViewController *commitViewController;
+
+	PBViewController* viewController;
 }
 
 @property (assign) __weak PBGitRepository *repository;

PBGitWindowController.m

@@ -10,7 +10,6 @@
 #import "PBGitHistoryController.h"
 #import "PBGitCommitController.h"
 
-
 @implementation PBGitWindowController
 
 
@@ -35,7 +34,11 @@
 
 - (void)windowWillClose:(NSNotification *)notification
 {
-	[viewController removeView];
+	NSLog(@"Window will close!");
+	if (historyViewController)
+		[historyViewController removeView];
+	if (commitViewController)
+		[commitViewController removeView];
 }
 
 - (void) setSelectedViewIndex: (int) i
@@ -49,16 +52,20 @@
 {
 	[self willChangeValueForKey:@"viewController"];
 
-	if ([viewController view] != nil)
-		[(PBViewController *)viewController removeView];
+	if (viewController != nil)
+		[[viewController view] removeFromSuperview];
 
 	switch (whichViewTag)
 	{
 		case 0:	// swap in the "CustomImageViewController - NSImageView"
-			viewController = [[PBGitHistoryController alloc] initWithRepository:repository superController:self];
+			if (!historyViewController)
+				historyViewController = [[PBGitHistoryController alloc] initWithRepository:repository superController:self];
+			viewController = historyViewController;
 			break;
 		case 1:
-			viewController = [[PBGitCommitController alloc] initWithRepository:repository superController:self];
+			if (!commitViewController)
+				commitViewController = [[PBGitCommitController alloc] initWithRepository:repository superController:self];
+			viewController = commitViewController;
 			break;
 	}