configure.ac: prepare for 0.19.7
playlist/Print: don't skip non-existent songs in "listplaylist"

Skipping those songs silently will confuse the client, because
commands specifying the song index within a playlist
(e.g. playlistdelete) will be out of sync.

This copies spl_print()'s behavior to playlist_file_print().
Merge branch 'v0.19.x'
src/win32: move resources to win32/