Port saving pages to packet handling framework

Any unhandled packets within pages are now loaded and saved intact
albeit with no way to edit them.

File handling is now two separate processes: parsing TTI files into
packets, and then interpreting the packets into how pages are
displayed. This will allow us to import other file formats, and to deal
with page functions other than Level 1 Teletext pages.

levelonepage.h

@@ -42,6 +42,7 @@ public:
 
 	TeletextPage();
 
+	QByteArray packet(int, int=0);
 	bool setPacket(int, QByteArray);
 	bool setPacket(int, int, QByteArray);
 	bool packetNeeded(int, int=0) const;
@@ -91,7 +92,6 @@ public:
 
 protected:
 	int controlBitsToPS() const;
-	QString x28toTTI(int);
 
 private:
 	unsigned char m_level1Page[25][40];