fix warning

- unused variable
- pid is uninitialized
use sigwait in main-loop
use raise instead of kill

make a purpose more clearly
neoagent does not handle SIGALRM
update doc
remove reload
make an end reload command
cast const char * -> char *
log files are not re-opened
fix invalid signal

when on-the-fly-update runs,
master should alert SIGUSR2 to worker processes
update completion

 * reload is obsolete
 * new commands
  * graceful
  * update
  * add
add new commands to help message
update doc

new functions: on-the-fly update, add-environment
neoagent v0.8.1~rc1 released
v0.8.1 released