Merge branch 'master' of /srv/git/nagcollect

* 'master' of /srv/git/nagcollect:
  Update ChangeLog for release 3
  Update README and INSTALL to describe active service checks
  Fix error message of wrapper script for active checks
  New make target "install-plugins"
  Use new make targets "server", "client", and "plugins"
  New make target "plugins" to generate active check scripts
  Add wrapper script for calling test scripts as active service checks
  Add .gitignore file
  Add "nagcollecttest" script
  RAID.tst: suppress warning and error messages