Adjust template to support images for individual blog posters

[ajg54]

Vonge as standard assumes that there is one author for the entire website. The code has already been adjusted to support changing the name of the author, but a proper way to support images (and bios, and author pages) for individual authors still needs to be implemented. This should be done by changing the template rather than manually requiring you to add a link to an image of the author in the preamble of each blogpost, just the name should be enough (as the template then knows where to pick-up the image).