Add browse request caching layer

[Petr Nejedly]

This would cahce browse requests (store the result objects). This is necessary for online sources (as it would take a long time to browse), but is useful also for local media metadata caching.

The cache can invalidate on timeout (online content) or manually (for local media, when update thread finds new content)

Cache will have limit and entries will be sorted by last accessed date, with the last in the stack removed when the limit is reached. This must be fairly quick, maybe a queue, with those most recently (or frequently?) items on the top to be accessed the fastest.

[Petr Nejedly]

added cachefor local content metadata to 0.4.1

[Petr Nejedly]

there is a bug where last viewed episodes don't refresh after viewed (as the titles are cached), so the cache should be cleared after a video is requested ? We could also have a cache per browse container and only clear those caches that are necessary.

[Petr Nejedly]

each command can have it's own region, some may share the same, e.g. local_Default, local_ResetAfterPlay

on view we could clean region local_ResetAfterPlay

cache invoking needs to be on a lower level, where we know content definition node

[Petr Nejedly]

the above is now done

[Petr Nejedly]

need more cahce for online sources