Zabbix

.......... [DEV-1136] improved configuration include value validation, added duplicated metric checks to user parameter initialization.

* commit '7a1358a6e9023eccfa26fd57ed3fdef81bbe9858':
  .......... [DEV-1136] changed Plugins option to be optional, fixed tests
  .......... [DEV-1136] Added plugin configuration file section
  .......... [DEV-1136] improved include parameter validation
  .......... [DEV-1136] disallow using relative paths in conf includes
  .......... [DEV-1136] added check for existing keys when registering user parameter
  .......... [DEV-1136] improved configuration file
  .......... [DEV-1136] added include directory and pattern support to configuration parser