More powerful index.html for http-screenshot

[freb]

One decent option would be to embed the images in the nmap xml output, but output an HTML file that could parse that xml and display the images. I dont' think this is easily doable with local files in a browser.

But, there are still some improvements needed:

• Images should be de-duplicated, and each host that has the same screenshot should be grouped. This will shrink the filesize and make validation of the targets easier (i.e. checking default creds)
• It would be nice to have additional script for filtering, sorting, de-duping (if necessary).