fix delete query for removing files if a spotify playlist is deleted
Merge pull request #74 from chme/spotify

fix delete query for removing files if a spotify playlist is deleted
Identify "android" user-agent as a remote client in transcode_needed()
(similar to the check in user_agent_filter())
Merge pull request #76 from chme/transcode

Identify "android" user-agent as a remote client in transcode_needed()
improve selects for files table by removing the join to the groups table
db update v16 and cache update v2
Improve selects for files table by removing the (f.album <> '' AND
f.album IS NOT NULL) from the where clause for album and artist. These
are unnecessary because forked-daapd makes sure that an artist or album
name exists.
Improve select for files table by removing f.media_kind = 32 from the
queries (forked_daapd has no media_kind = 32).
Optimize the indexes on the files table to speed up select queries
optimize queries and indexes for composer/genre
Initial support for mpd protocol