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
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
curl_json plugin: style cleanups