Switch to generic Spring HATEOAS links

* Use ModelAndView to support using Spring HATEOAS linkTo(methodTo()) ops
* Include link back to All Images when viewing single image
* Create _links template with fragments
* Embed generic listing of links fragment, use it for oneImage template
* Embed "Come see presentation at SpringOne" fragment and include it at bottom of all pages
Remove unneeded throws clause
Merge pull request #10 from gregturn/linkify

Switch to generic Spring HATEOAS links