* clear_audio_cache is now invoked also from:
- when a sound file is added (to reflect use_parent/potential child
sets)
- when a parent is changed for a sound set (to reflect current
and potential child sets)
- when a sound set is removed (to reflect potential child sets)
* clear_audio_cache() is reworked
- clear_audio_cache() now calls virtual_child_sound_sets to
fetch all potentially affected child sound sets and also
clears audio cache for them. if the amount of fetched
sound_sets is greater than 10000 then the the whole audio
cache is invalidated
* _clear_audio_cache_service() is reworked
- supports/expects a list of sound sets and sends them
as a string with ':' separator
- if both sound handle and sound sets are provided it calls
clearFiles (so that only the specific sound handle is cleared)
- if only sound sets are provided it calls clearSets (so that
all of the cached files beloning to the sets are removed)
- if none of the above are provided it calls clearAll to invalidate
the whole cache
Change-Id: Ie85f208e27183e88665803b93bb16d7de8e3d7ac