Criticality filter (Centreon 2.4)

Add one more regex filter, based on Centreon criticality field. In
centreon, this property can be set for hosts and services independently.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Conditional visibility of criticality options

Show the criticality options only when server type Centreon is enabled
Remove a local customization
Merge pull request #32 from foscarini/master

Add regex filter by Criticality property from Centreon