Merge branch 'dev'
Enable http response time monitoring, using httping.

This commit fixes #81.
Merge branch 'id/81' into dev
Merge branch 'dev'
Monitor Redmine Web Service Response time.
Merge branch 'id/84' into dev
Merge branch 'dev'
Make directories to collect server and service configuration.

- /etc/nagios/servers
- /etc/nagios/services
Merge branch 'id/87' into dev