Help file added for webservers

One of the biggest issues while installing Fork is that the *.htaccess* file doesn't get uploaded, which breaks the url rewriting. When this happens, the user goes to his url and gets redirected to *install/* and everything breaks.

If we simply put an *index.html* with a proper explanation of what went wrong we can get the user back on track.

I used the maintenance page from fork-cms.com as design.

![schermafbeelding 2013-06-03 om 10 53 35](https://f.cloud.github.com/assets/1014380/598471/0db43304-cc2e-11e2-9e59-a696d8a3791e.png)