Create page helper for pulling relative image path
Use flexible path for tile URLs

Uses new relative_image_path helper to ensure JP2 *or* TIFF are pulled
depending on configured settings
Use central tile path for printable page

Uses chronam_image_tile instead of the very similar but separate
chronam_page_image_tile
Remove obsolete image URLs and handlers

Removes page_image and page_image_tile - the former doesn't appear to be
in use anymore, and I just destroyed the latter
Remove unused "medium" URL
Add resize URL and handler
Use resize URL/handler for thumb / medium image
Fix example for thumbnail caching
Add example for proxying resize to external server

Allows tiles and thumbnails/medium JPGs to go through an external
server, thus removing *all* image derivatives from chronam
Trim down WSGI process count

- Drops all reference to chronam-wsgi-images
- Halves process and thread counts for chronam-wsgi-app
- Sets max requests to 10,000 for chronam-wsgi-app just in case of
  memory leaks

There is no more need for image-specific processes, and the rest of the
app seems to run just fine at the moment.  Obviously this is pretty
UO-specific, and is a VERY BAD idea for anybody without an external
image server.
Fix thumbnail on newspaper title page
Don't serve JSON coordinate files through django!
Merge branch 'feature/centralize-dynamic-image-paths'