killall, pidof: use argv0 for process matching too

killall, pidof: use argv0 for process matching too
top: show cmdline, not comm field
(fixes problems with re-execed applets showing as processes with name "exe",
and not being found by pidof/killall by applet name)

function                                             old     new   delta
find_pid_by_name                                      98     156     +58
procps_scan                                          692     732     +40
top_main                                            2724    2762     +38
find_pair                                            164     180     +16
collect_int                                          114     123      +9
cmp_main                                             547     555      +8
collect_fork                                         112     119      +7
collect_ctx                                          112     119      +7
read_package_field                                   253     257      +4
passwd_main                                         1983    1985      +2
process_stdin                                        435     433      -2
xstrtoul_range_sfx                                   229     226      -3
get_next_block                                      1852    1849      -3
arith                                               2042    2033      -9
sv_main                                             1236    1226     -10
singlemount                                         4690    4672     -18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 10/6 up/down: 189/-45)          Total: 144 bytes
   text    data     bss     dec     hex filename
 734789    3028   14400  752217   b7a59 busybox_old
 734933    3028   14400  752361   b7ae9 busybox_unstripped