Fixed size-links and missing-geotag handling

The "Other Sizes" links are now defined relative to the current URL, so they should not break when the app root is prefixed (eg. with /photicle/).
When there is no geo data for a photo, its detail page will no longer show a map link.
Merge pull request #1 from sethaurus/patch-1

Fixed size-links and missing-geotag handling