Settings/Preferences navigation refactor 2. Part of plexinc/plex-home-theater#925
Use Settings slideshow for Skin Settings window.
Hide Settings slideshows when the preference is activated.
First step for both video/music pq lists at home screen.
The OSD needs to have ID=1111 for us to hide it.

Part of plexinc/plex-home-theater#1254
[PAGING] Add PauseRendering Function to PlexUtils

Renderloop being very nasty on Rpi, we want to pause it to get max juice available when doing some heavy processing.
[PAGING] Style fixes
[PAGING] New Paging implementation

This one replaces the old one. it will fecth only the required pages and will keep track of them so that we dont have to fetch everyting in between when jumping.

It requires USE_PAGING to be defined.
[PAGING] Make PlexUtils::PauseRendering increment threadsafe
[PAGING] Add USE_PAGING option to CMakeConfig.
[RASPLEX] Adding PlexGlobalCacher

This is the global precaching implementation that we introduced on RPi.
Allows to precache all the sections image at once so that the GUI experience doesnt lag forever
Fix [Skin] Preferences top level browsing is confused #925
Adding PlexDirectoryCache

This is my directory Cache implementation with test cases :)

Will store the FileItemlist for a directory and the assicated xml hash.
This allows to avoid the parsing process when nothing has changed.

I have set Fanouts to CACHE_ALWAYS & directories are cached upon itemcount.
Fix Compilation Warning in globalCacher
Introducing Plex TextureCache

This is an Plex Implementation of TextureCaching. It inherits from the XBMC implementation which uses a Database. Plex doesn't need to have a database and some benchmarks have proven that using the database makes everything crawl.

We therefore only use the Thumbnails local storage which is enough for our use.
Fix Paging Build errors
Use Paging on RPi
Working towards 1.2.0 here now.
g_plexApplication.directoryCache might not be inited always
Fix tests for PlexDirectoryCache.