signal: cleanup

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
Linux kernel linked list for user space

Code can be downloaded from:
http://www.mcs.anl.gov/~kazutomo/list/

CREDITS goes to kazutomo

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
ignore vi swap file

Signed-off-by: Fudong Bai <fudongbai@gmail.com>