Merge pull request #989 from alanwww1/modified_po_format

Advanced PO file format
updated: Czech translation for core strings (thanks to Tomáš Chvátal)
videodb: add fields, group and limit to CVideoDatabase::Filter
videodb: move set retrieval logic from GetSetsNav to GetSetsByWhere
videodb: adjust implementation of GetSetsByWhere to determine metadata for sets
videodb: fix retrieval of movies being part of a set

The problem is that we only retrieve sets if they contain more than one movie
(which is handled through SQL's COUNT() and GROUP BY on the setlinkmovie table).
The existing logic does not take into account special WHERE conditions like when
browsing movies by years which can result in a set being found which usually
contains multiple movies but combined with the special WHERE condition, only one
movie matches the whole query. In that case up until now neither the set containing
the matching movie nor the movie itself were listed.
cosmetics: sort LabelFormatter options alphabetically for easier reading
cosmetics: fix labelmask comments in GUIViewStateVideo
GUIViewStateVideo: adjust labelmasks to display year, rating, playcount, lastplayed and dateadded for sets
GUIViewStateVideo: add sorting by year, rating, dateadded and playcount to the movie sets node
[osx/ios] ignore xcode4 user settings
[osx] changed to match depends default build, use 'latest' SDK and target 10.6 as min. Note to osx devs, make sure any new APIs are present in 10.6 sdk. removed double CoreFoundation framework ref
[osx] fix compile warning
[osx] fixed compile warning
fixed compiler warning spew under clang 'indirection of non-volatile null pointer will be deleted, not trap'
don't map 'end' key to Shutdown()
[osx] README.osx location changed in Xcode project
support &#[0-9]{1-5}; in XML entities. fixes #13059
update CXBMCTinyXML::Test() to correctly verify hex and decimal XML entities
don't hit iterators during RunStreamStage unless we have to - win32's debug stl grabs global locks which makes debugging painful