check_nt: add UPTIME to perfdata

Just turning attached patch of github issue #1024 into a push request.
Updated FSF address in perl scripts.  thanks for the heads up github user lrupp
Revert "check_nt: add UPTIME to perfdata"

Decided to add options for the time unit for the perfdata.
This reverts commit f435b5740c7ea2e5c97d84dc4a303ab7f333714c.
Updated NEWS
check_ifstatus: perfdata bug

Just turning attached patch of github issue #721 into a push request
Added perfdata to check_nt.  New -l options -  seconds|minutes|hours|days.
Merge branch 'maint' of https://github.com/nagios-plugins/nagios-plugins into maint