nsd_: new plugin to monitor NSD name servers

This plugin collects most statistics from NSD name servers.  It
should be called nsd_by_type, nsd_by_rcode or nsd_hits to monitor
queries received by type, replies sent by rcode or the base query
volume, respectively.  The plugin is friendly to the name server
and only sends one signal per run (even if three links exist).
Create virtualbox_cpu_kernel

This graph shows the percentage of processor time spent in kernel mode by the every single VM process.
Create virtualbox_cpu_user

This graph shows the percentage of processor time spent in user mode by the every single VM process.
Create virtualbox_ram_usage

This graph shows the ram usage of every single VM process.
Add PHP OPcache plugin
Fix indentation
rg: first attempt of munin plugin to monitor ArangoDB database
Plugin to monitor uWSGI Average Memory Usage, Number of Process & Total Memory Used
Create voltcraft_tcm220_

Munin plugin to monitor values reported by a Voltcraft TCM 220 or 320 temperature swicth module connected to a serial port.
Added a plugin to check SSL certificate expiry times

This plugin connects to remote hosts and checks the HTTPS certificate
expiry time.

Example: https://munin.buddycloud.com/ssl-day.html
more sensible subdirectory name (ssl_certificates -> ssl)
Create eatonups_

Multigraph munin plugin to monitor Eaton UPS-es through the web interface of the SNMP add-on card.
Create 2wcomdsr_

Multigraph munin plugin to monitor 2wcom DSR01/DSR02 Professional Audio Satellite-Receivers through their web interface status page.
Plugins for Bitcoin-Miner Hashrates (btcguild and slushs pool)
Create dovecot_stats_
reward plugin for slushs pool
- Fixed key that was based on $index and no unique name (when you changed a url, old stats were kept)
- Indentation changed to soft tabs
Update bitcoind_

Removed dependencies of blockchain.info - so no call to anything else than the local bitcoind
fping_ => Added file to monitor server/network availability
fping_ => Added informations and fixed a bug