Improve SQM logging

Wrap all calls to logger in functions.sh in sqm_logger() which appends
 "-t SQM". So the output changes from:
Fri Jul 25 09:43:24 2014 user.notice root: get_limit:  CURLIMIT: 1001
to Fri Jul 25 09:43:24 2014 user.notice SQM: get_limit:  CURLIMIT: 1001
Also append "-s" so that the output is also directed to stderr so
there is a bit output when called via "/etc/init.d/sqm start".
Improve the logging of run.sh

Change the logging in run.sh, to show thw tag "SQM" instead of "root",
also log to stderr.
Improve logging by using SQM as tag

Make stop.sh also use sqm_logger from sqm/functions.sh
Improve logging of simplest.qos

Make simplest.qos use the logger wrapper from sqm/functions.sh.
mproce logging in simple.qos

Make simple.qos use sqm_logger from sqm/functions.sh instead of
open coding it.
Fix the sqm_logger function in sqm/functions.sh

Typo in the function name needed fixing, ist sqm_logger,
not sqm_sqm_logger...
Fix sqm_wrapper to actually log the passed string
Make sure sqm_logger() is defined before calling it...
Avoid hardcoding the ifb device in sqm/functions.sh's diffserv()

The SQM system currently can be depoyed on multiple interfaces, so
ARP hanfling of diffserv() should be applied to the IFB associated
with the current instance of SQM.
Be more verbose about DSCP squashing and interpretation

Teach simple.qos to give some output about the DSCP handling options. Also
remove "-x" from simple.qos' shell invocation, since this is only needed for debugging.