set of updates for Polish recipes
Add a tweak to change the image compression quality used by the content server when it makes thumbnails.
Remove Bookoteka store, as they don't sell ebooks any more
Add some recipes of Uruguay.

Add 10minutos.recipe (News of Salto)
Add diario_el_pueblo.recipe (News of Salto)
Add diario_salto.recipe (News of Salto)
Add unoticias.recipe (News of Montevideo)
Add padreydecano.recipe, update el_observador...

Add padreydecano.recipe (C.A. Peñarol related news)
Update el_observador.recipe it was broken for a long time.
Use much less memory when reading and writing cache
More cache work -- remove some code, get rid of old file.
ebookpoint plugin: exclude audiobooks from list of items
Make metadata cache reading slightly more robust
remove 'The H' recipe

Unfortunatelly they're not publishing any more:
http://www.h-online.com/open/news/item/The-H-is-closing-down-1920027.html
Fix virtual libraries template function

The virtual libraries template function was overriding the cache used
for format_metadata in the ProxyMetadata object.
Update Neu Osnabrucker Zeitung
Update AM 730 and Ming Pao (HK)
calibredb: Allow setting fo title sort field

Fixes #1233711 [CalibreDB: title_sort is not a known field](https://bugs.launchpad.net/calibre/+bug/1233711)
DOCX Input: Handle numbering without character styles

DOCX Input: Fix erorr when converting docx files that have numbering
defined with no associated character style. Fixes #1232100 [Private bug](https://bugs.launchpad.net/calibre/+bug/1232100)
Display version on Kobo unsupported firmware message

When calibre shows the message that says the Kobo device is not
supported, the firmware version and database version on the device is
not displayed. Adding this to make support a little easier.
...
...
Update Carta Capital

Fixes #1235052 [News "Carta Capital" is not working](https://bugs.launchpad.net/calibre/+bug/1235052)
HTML Input: Handle the poster attribute of the <video> tag

HTML Input: Images linked by the poster attribute of the <video> tag are now
recognized and processed.