- sorted out according to recurring logic that wants function
  prototypes in separate files from data struct and constants
  definitions, variables in separate .c files with inclusion
  of "extern" header files
- moved function prototypes to resective header files
- moved data structures and constants to respective header files
- merged unnecessary mac.h file into mac_defs.h @ MAC UE
- moved const variables suchs as tables to respective .c files
- moved extern references to respective extern.h files