Allow proxying local image files
Allow FolderInfo handlers to be browsed into

Allow folder info handlers to return xmlbrowser hashes which can be
browsed into, persist the returned feed for the session and browse into
it as otherwise we return with bad params when browsing into a feed
Make artwork in songinfo page clickable, to be shown full size in a new
window/tab
Use image's text as an alternative for its description.
Minor tweaks to the web UI

- make EN skin look slightly less ugly
- improve UX on mobile devices using EN skin
Merge branch 'public/7.7' into public/7.8
Changelog update
Add link to image file to the lightbox' caption.
Disable some test code
MSIE 11 now return empty cookies as an empty string instead of null
Return quickly if cache already has been initialized
Merge branch 'public/7.7' into public/7.8
Two more cases where we can end up with non-absolute URLs. Make sure we
add the "webroot" in those cases.
Merge branch 'public/7.7' into public/7.8
Some DB tweaks for improved performance

- Tweak wal_autocheckpoint depending on whether we're running scanner or
server code. Scan is heavy on writes. Using a larger checkpoint interval
can greatly improve scan performance on slow disk systems.
- Move db configuration into DbCache base class to allow all cache
classes to use the highmem settings.
Bug 18053 - Windows doesn't go to sleep

Don't consider UPnP requests client requests. UPnP clients are
polling all the time - which prevents LMS from letting Windows go to
sleep.
Changelog update
Merge branch 'public/7.7' into public/7.8
Remove debug statement
Merge branch 'public/7.7' into public/7.8