clean up CPP includes

Include only headers which are really required.  This speeds up
compilation and helps detect cross-layer accesses.

src/player.c

@@ -20,16 +20,8 @@
 #include "path.h"
 #include "decode.h"
 #include "command.h"
-#include "interface.h"
-#include "playlist.h"
-#include "ls.h"
-#include "listen.h"
 #include "log.h"
-#include "utils.h"
-#include "directory.h"
-#include "volume.h"
 #include "playerData.h"
-#include "permission.h"
 #include "ack.h"
 #include "os_compat.h"
 #include "main_notify.h"