[Crash-utility] "gdb" by itself ought to put crash into a "gdb" mode

Hi, I might actually write the patch for this one. Piping back to crash, as useful as it would be, requires too much context shuffling. Here, all that'd be necessary is a "we are in pass through to gdb" mode meaning that the "gdb " prefix to gdb commands would not be necessary. Just monitor the input for a "crash" line and flip the bit. It's a nuisance to have to remember that prefix when typing a long series of gdb commands that mostly work as crash commands. Possible? Thanks ! Regards, Bruce