replace framebuffer.h include with forward declaration

instead of including framebuffer.h almost everywhere, replace it with
class CFrameBuffer forward declarations and/or generic system includes.
Add a hack to define fb_pixel_t to config.h (one reason for
framebuffer.h includes was the fb_pixel_t define)

src/gui/epgview.h

@@ -33,7 +33,6 @@
 #ifndef __epgview__
 #define __epgview__
 
-#include <driver/framebuffer.h>
 #include <driver/rcinput.h>
 #include <driver/fontrenderer.h>
 #include <system/settings.h>
@@ -50,6 +49,7 @@
 
 #define BIG_FONT_FAKTOR 1.5
 
+class CFrameBuffer;
 class CEpgData
 {
 	private: