Added new tool: snmpwalk-worker

Small tool that queries SNMP devices. It produces the output
that is used by snmp/snmp_preprocess.py
Added two more tools

- dump_data_dir.py
	Uses the output of the snmpwalk-worker to generate
	temporary files that can be used to update rrd files
- update-rras
	Usese the output of dump_data_dir to update a list
	of rrd files
Make sure that the tag _id is changed on the fly
snmp_preprocess: IP range calculation optimization

The ip ranges for cEigrp and ipCidrRoute have perviously
been calculated using database requests after the parsing
was completed. We are now creating them on the fly while
inserting the data into the DB:
SQL backends: allow insert instead of update
Merge branch 'master' into merge-from-timm
Sqlbasebackend: drop out on exceptions

if the sql backends don't know how to handle some DB errors, they
will rerasie the exception. Drop out of the program in this case
and log some more information
Move DB and SNMP config files to config directory
Provide default argument parser
Moved coded from snmp_preprocess --> common_functions

The field dict generation code is used by more scripts and
was therefore moved to common_functions.py
Device management

Add devices to the database and prepare files for the
querying by the tools in tools/
Refactoring of add_devices_to_monitoring.py
Python script for performing online checks on monitored devices
Small c++ utility that allows to replace fping
Make mysql return OrderedDicts
snmpwalk-worker can now perform availability checks
do_live_check --> do_poll_check.py

Script can now check for snmp availability
snmpwalk-worker reads hosts from stdin
update-rras: take single cache file instead of cache dir
New script for performing the snmp_measurements