SIGNALS:
Here follows a list of supported signals and their meaning; remember
that pmacct core says goodbye when its last child dies or is terminated.


pmacctd core process:
SIGCHLD:	used to handle gracefully his loved child processes;
SIGHUP:         causes the reopening of connection with syslog daemon;
SIGINT:		ignored;
SIGPIPE:	ignored;

MySQL plugin process:
SIGPIPE:	inherited by parent process (pmacctd core);
SIGCHLD:	inherited by parent process (pmacctd core);
SIGHUP:		inherited by parent process (pmacctd core); 
SIGINT:		causes the process to exit gracefully;	

PGSQL plugin process:
SIGPIPE:        inherited by parent process (pmacctd core);
SIGCHLD:        inherited by parent process (pmacctd core);
SIGHUP:         inherited by parent process (pmacctd core); 
SIGINT:         causes the process to exit gracefully;

In-memory table process:
SIGPIPE:        inherited by parent process (pmacctd core);
SIGCHLD:        inherited by parent process (pmacctd core);
SIGHUP:         inherited by parent process (pmacctd core); 
SIGUSR1:	internal use; causes clearing of in-memory table; 
