Reset playlist and library functions

These functions should be called to reset the library and playlist,
which is better than deleting the old files and making a new one.

libsaria/collection/__init__.py

@@ -38,6 +38,11 @@ def walk_library():
 	for track in library.walk_tags():
 		yield track
 
+def lib_reset():
+	global library
+	library.reset()
+	library.save()
+
 def lib_get_attr(id, attr):
 	global library
 	if id >= 0:
@@ -109,6 +114,11 @@ def plist_filter(text):
 	global playlist
 	return playlist.filter(text)
 
+def plist_reset():
+	global playlist
+	playlist.reset()
+	playlist.save()
+
 def plist_refresh():
 	return call("PLISTREFRESH")