Extract messages to a C structure

Modules
	Farm control message structures
	Job message structures
	Raster management message structures
	Status message structures
	Notification message structures

Detailed Description

Functions for extracting the payload of messages received from message_callback() into a C structure. The functions are spread amongst these functional groups:

• Farm control (Farm control message structures)
• Job control (Job message structures)
• Raster management (Raster management message structures)
• Status (Status message structures)
• Notifications (Notification message structures)

Only one of the rf_extract_message() functions is appropriate for a given message, as determined by the msg_type field in the farm_reply param of all messages. The returned C structure should be freed using the appropriate rf_free_message() function when it is no longer required.