Clean up getTime helpers

This increases size of the getTime return values to 64 bits.
It also removes the TimeGetter classes since the getTime functions
are now very precise.

src/guiChatConsole.h

@@ -98,7 +98,7 @@ private:
 	v2u32 m_screensize;
 
 	// used to compute how much time passed since last animate()
-	u32 m_animate_time_old;
+	u64 m_animate_time_old;
 
 	// should the console be opened or closed?
 	bool m_open;