[Crash-utility] Update of list to accept several options -s x.a -s x.b -s x.c

Hi Dave, I hope this does not break anything. Very usefull for me to be able to view a chosen list of fields. Later i shall implement : -s x.a,b,c (as a shortcut for -s x.a -s x.b -s x.c) Olivier [root@fedora4 crash-4.0-3.6-patch]# ./crash -s crash> list file_lock.fl_link -s file_lock.fl_pid -s file_lock.fl_wait -H c036acf4 f6f795e0 fl_pid = 2962, fl_wait = { lock = { slock = 1, magic = 3735899821, break_lock = 0 }, task_list = { next = 0xf6f79608, prev = 0xf6f79608 } }, f6f79b58 fl_pid = 2977, fl_wait = { lock = { slock = 1, magic = 3735899821, break_lock = 0 }, task_list = { next = 0xf6f79b80, prev = 0xf6f79b80 } }, [...]