iStock search/lightbox result modifications

Description

Adds features to the iStock search results pages that are useful for contributors. "Search results pages" includes portfolio pages and lightbox pages. Features include:
- files owned by the contributor are highlighted;
- the number of files on this page which are owned by the contributor is displayed;
- royalty for each of the contributor's files on this page can be displayed;
- total royalty for all of the contributor's files on this page can be displayed.

v0.1.1:
Don't highlight the search results when you own all the files found (e.g. looking at your portfolio or lightboxes of your own files).

v0.1.2:
iStock changed the search results layout.
v0.1.3:
style fixes; make the royalty visible in the new layout.
v0.1.4&5:
redraw the highlight when the search criteria change.
v0.1.7:
graphs of stats for the last year when you click the "Royalty" button.
v0.1.8:
fix for the buggy loupe styling.
v0.2.0:
Loupe done right:
- don't wait for data to load before showing the image;
- don't cover the image you're over
- don't make it hard to move to the next image
- don't disappear off the bottom of the screen(!)
Disable the Royalty button if none of the displayed files are yours
Old style search icons (red editorial; exclusive crown)
v0.2.1:
Dynamic preview for video and audio.
v0.2.2:
Settings on the regular iStock preferences page.
v1.0.0:
Zoom the loupe image on the search results page using '1', '2', '3'.
v1.0.1:
Now works when the search path is /royalty-free/...
v1.0.2:
Cope with a change iStock made to the loupe scripts.
v1.0.3:
New preferences option to use the iStock loupe;
Add icons to add a file to a lightbox (or remove it if we're in a lightbox view).
v1.0.5:
Compare large thumbnails in a sidebar.
v1.0.6:
Fixes for changes to the iStock site.
Easier to dismiss the large sidebar thumbnails.
v1.0.7:
Fixes for the loupe when showing large thumbs.
Show a collection indicator when possible.
v1.0.8:
Recent site changes broke the collection indicator. This should fix it.
v1.0.9:
Recent site changes broke the loupe, zoom and large comparison thumbs. This should fix them.
v1.0.10:
Better zoom tracking for both sizes of thumbnails.
Add a zoom icon to the thumbnail mouse-over icons.
Add shortcut buttons to the File Edit and File Downloads pages for your files.
v1.0.11:
Fixes for recent site URL changes.
v1.0.12:
Main collection is now Essentials.
Include subs in royalty totals and graphs.
v1.0.13:
Fix for recent istock changes.
Highlight non-zero royalties.
v1.0.14:
istock case changes.
v1.0.16:
optionally show stats for last year as well as this year.