Make it possible to have implementations in different toolkits.

Also, make it possible to share the headers.

OGButton.m

@@ -1,56 +0,0 @@
-#import "OGButton.h"
-
-@interface OGButton ()
-- (void)OG_clicked;
-@end
-
-static void
-clicked(GtkWidget *widget, gpointer data)
-{
-	[(OGButton*)data OG_clicked];
-}
-
-@implementation OGButton
-@synthesize delegate;
-
-+ button
-{
-	return [[[self alloc] init] autorelease];
-}
-
-- init
-{
-	self = [super init];
-
-	widget = gtk_button_new();
-	g_signal_connect(G_OBJECT(widget), "clicked", G_CALLBACK(clicked),
-	    self);
-
-	g_signal_connect(G_OBJECT(widget), "destroy", G_CALLBACK(og_destroy),
-	    self);
-	[self retain];
-
-	return self;
-}
-
-- (OFString*)label
-{
-	return [OFString stringWithUTF8String:
-	    gtk_button_get_label(GTK_BUTTON(widget))];
-}
-
-- (void)setLabel: (OFString*)label
-{
-	gtk_button_set_label(GTK_BUTTON(widget), [label UTF8String]);
-}
-
-- (void)OG_clicked
-{
-	OFAutoreleasePool *pool = [OFAutoreleasePool new];
-
-	if ([delegate respondsToSelector: @selector(buttonWasClicked:)])
-	      [delegate buttonWasClicked: self];
-
-	[pool release];
-}
-@end