Handle responsive images

[bwthomas]

src attributes are handled, but not srcset which provides a comma delimited list of image urls to be used for different screen sizes. More info on srcset here.

Ultimately I'll take a look forking & issuing a pull request, but I thought I'd log the issue for the moment.

[ashuvssut]

@bwthomas did you find any solution to this? Maybe some other library?