libsaria: Added a REFILTER callback

This will be called to inform the UI that the filter text has changed.

include/libsaria/callback.h

@@ -8,6 +8,7 @@ enum callback_t {
 	TRACK_LOADED,
 	IDLE_TASK_QUEUED,
 	LIBRARY_REFRESH,
+	REFILTER,
 };
 
 void register_callback(callback_t, void (*)());

libsaria/library/index.cpp

@@ -4,6 +4,7 @@
 #include <algorithm>
 using namespace std;
 
+#include <libsaria/callback.h>
 #include <libsaria/format.h>
 #include "library.h"
 
@@ -163,6 +164,7 @@ namespace libsaria
 			do_filter(key_list);
 			filtered = true;
 		}
+		trigger_callback(REFILTER);
 	}
 
 }; /* Namespace: libsaria */