Replacement for check_http from the nagios-plugins package.

Feel free to contact me at <abaumann at yahoo dot com> in case of questions,
suggestions, patches, etc.

Differences to check_http:
- Additional option --config-file <configfile>, a gengetopt feature, allows
  storing command line options in a configuration file

Status of supported options:
- -w and -c support only fixed values, no ranges