Zabbix

.......... [DEV-1254] Port items collection C code in to go agent

* commit '364a04806932e276fb00ed384a65f8a97c4c2da7': (71 commits)
  .......... [DEV-1254] fix error message
  .......... [DEV-1254] added description to test plugins and user parameters
  .......... [DEV-1254] added also metric format validation during registration
  .......... [DEV-1254] replace to plugin.RegisterMetrics().validation of plugin description on Title and dot at the end of description
  .......... [DEV-1254] adjusted testing output to match zabbix agent output
  .......... [DEV-1254] set all metrics for print (-p) as in C agent
  .......... [DEV-1254] set default value of 'agent.Options' in case of '-t' or '-p'
  .......... [DEV-1254] remove c call 'system.cpu.num'
  .......... [DEV-1254] moved system.swap.* to single thread due to stat() and sysinfo()
  .......... [DEV-1254] c call 'vm.memory.size'
  .......... [DEV-1254] c call 'vfs.fs.size'
  .......... [DEV-1254] c call 'vfs.fs.inode'
  .......... [DEV-1254] c call 'vfs.fs.discovery'
  .......... [DEV-1254] c call 'vfs.file.time'
  .......... [DEV-1254] c call 'vfs.file.size'
  .......... [DEV-1254] c call 'vfs.file.regmatch'
  .......... [DEV-1254] c call 'vfs.file.md5sum'
  .......... [DEV-1254] c calls 'vfs.dir.*'
  .......... [DEV-1254] c call 'system.users.num'
  .......... [DEV-1254] c calls 'system.swap.*
  ...