flatten arranger and piano modules

src/arranger/arranger_v_io.rs

@@ -0,0 +1,26 @@
+use crate::*;
+use super::*;
+
+pub struct ArrangerVIns<'a> {
+    size:   &'a Measure<Tui>,
+    tracks: &'a Vec<ArrangerTrack>,
+}
+
+from!(<'a>|args: &'a ArrangerTui|ArrangerVIns<'a> = Self {
+    size:   &args.size,
+    tracks: &args.tracks,
+});
+
+render!(Tui: (self: ArrangerVIns<'a>) => "");
+
+pub struct ArrangerVOuts<'a> {
+    size:   &'a Measure<Tui>,
+    tracks: &'a Vec<ArrangerTrack>,
+}
+
+from!(<'a>|args: &'a ArrangerTui|ArrangerVOuts<'a> = Self {
+    size:   &args.size,
+    tracks: &args.tracks,
+});
+
+render!(Tui: (self: ArrangerVOuts<'a>) => "");