Add UI to change request method

I often see buggy servers that give me a server error 500 if the link is checked via HEAD method.

This is wrong behaviour and we should get a 405 (method not allowed) that makes link checker automatically change the request method and re-check the link. Users should be able to change the check method via a select box. It's very technical and we need to explain in a very easy manner what the method is.

Here are a few examples of such buggy servers:

http://www.forum-sozial.de
http://www.kinderundjugendtelefon.de/eltern.html
http://www.zeitgeist-uhrenmuseum.de/
http://www.naturfreundejugend.de/

If someone has an idea how it is possible to configure a webserver in such a wrong way, please give me a hint.