Added "gid" keyword to print effective group ID of process.

Added "gid" keyword to print effective group ID of process.
(also alpha-sorted some of the man page that was nearly sorted.)

BEFORE:

kstailey@hermes$ ps -o ruid,svuid,uid,command
 RUID SVUID   UID COMMAND
  333   333   333 -bash (bash)

worked, but group equivalent failed:

kstailey@hermes$ ps -o rgid,svgid,gid,command
ps: gid: keyword not found
 RGID SVGID COMMAND
   20    20 -bash (bash)

AFTER:

kstailey@hermes$ ps -o rgid,svgid,gid,command
 RGID SVGID   GID COMMAND
   20    20    20 -bash (bash)