Add support for OpenVPN 2.3.0 status files.

Fix a bug that breaks this module if a server is running multiple instances of OpenVPN and one instance does not have any clients connected.
[perl_openvz] allow simulated plugins to be enabled and disabled
[perl_openvz] use hostname over veid
[perl_openvz] ignore lo interface. report like the real plugin does
[perl_openvz] fix update error
[perl_openvz] rework read_interface
make this a little more perly
typoed ref to hash; copy values
Merge pull request #1 from jyotty/cl/perl-openvz

Cl/perl openvz
[perl_openvz] fix missing semicolon from @jyotty
Add Alias and ConnectTimeout options to MySQL plugin
Included memory usage per VM

Included all the metrics about the actual memory used by VMs (as
returned by libvirt.virDomainMemoryStats)
Drop st_mysql_options and use db->con->options instead
Annotate meta data for db plugins

Provide a MetadataFrom setting to name columns whose content is to be
added as metadata to the data collected.  Similar in usage to the
ValuesFrom setting.
add log_logstash plugin to emit logstash json_event messages.
Add SNMPv3 authentication and encryption support

Adds the following configuration options to support SNMPv3 authentication:
* SecurityLevel - authPriv | authNoPriv | noAuthNoPriv
* Username - username for authentication
* AuthPassphrase - passphrase for authentication
* AuthProtocol - MD5 or SHA
* PrivacyPassphrase - passphrase for encryption
* PrivacyProtocol - AES or DES
* Context - Optional authentication context
Add PluginInstanceFormat option to add plugin instance support
curl_json plugin: separate the cj_curl_perform in to the curl and yajl parts
curl_json plugin: support getting json from a Unix socket as well as a URL
curl_json plugin: use sstrerr for thread safety