Initial theme support!

This should help with #4 and others making variants. If you have something finished, please do a pull request and I'll make it part of future releases!

Expected theme folder structure:

comixology2 > themes (you need to create this) > [theme name] > [theme name].css
(ie. comixology2/themes/dark/dark.css)
Also copy the 3 logos into your [theme name] folder.

Set var themeVariant=[theme name]; in your settings.js to enable.
(ie. var themeVariant="dark";)

Fix for invalid parentIDs end caching (ie. from search)

This was breaking for anything that was first seen via search, since it set the parentID to "?search=true" instead of a number.

Search results now splits into categories, css tweaks for progress bars

Issues and series are now split in search results, and if their parent is the storyarcid then they're split into a 3rd category.

This doesn't work for story arcs split into different sub-folders yet, as that would need more checks.

Progress bars and higher res logos

With a big help from DarkShadowSwE, comics now indicate progress on the page (books require some metadata I can't access yet). If you've read past page 1 of any comic, a progress bar is displayed under the cover image.

And some new logos from SwedishGojira since I made my pngs too small (and so the logos are blurry on higher dpi displays).

Pagination for script-generated pages!

Bookmarks page uses its own limit (15) since covers are larger and 5-wide. JSON-based story arcs/book series follow comic page length.

Also caught a bug where bookmarks on the homepage weren't following the limit.

Fix for arc numbering

Now if there's a story arc page link in breadcrumb it'll run containerWrap('arc') otherwise containerWrap() when buildBreadcrumb finds the base link.

Read button moved back to dynamic function

So Ubooquity can supply the page count and progress bar works correctly again.

Minor fixup for old folder-info setups

And now arcRunner uses enableFolderMetadataDisplay to determine if it loads the templates.

Breadcrumb nav now generates complete path

New breadcrumb nav function is no longer limited to just Type > Parent > Current.

Now it'll go as far as it can:

Comics > Story Arcs > DC > Whatever category > as > many > as > you > want

And it caches everything it looks up, so at worst it'll only be slow once.

Navigation header now handled with all IDs instead of classes

Not normally necessary, but this improves older browser support. It hurt to write.