Flight rec data dump with gdb script
This adds a gdb script and a global variable that points the ring buffer as to display the contents of flight recorder in case of a core-dump.
A continuation for !144 (comment 145935)
Once in gdb source the script and call 'display_flight_rec' to dump the data.
The symbol must be present, initialized and not empty in order to display its contents. The data
can also be accessed calling the function
this can't be used in core-dump situation only when the program is a running state.