wip: refactor into fewer crates

crates/engine/examples/midi-import.rs

@@ -0,0 +1,17 @@
+use tek_midi::*;
+use tengri::input::*;
+use std::sync::*;
+struct ExampleClips(Arc<RwLock<Vec<Arc<RwLock<MidiClip>>>>>);
+impl HasClips for ExampleClips {
+    fn clips (&self) -> RwLockReadGuard<'_, Vec<Arc<RwLock<MidiClip>>>> {
+        self.0.read().unwrap()
+    }
+    fn clips_mut (&self) -> RwLockWriteGuard<'_, Vec<Arc<RwLock<MidiClip>>>> {
+        self.0.write().unwrap()
+    }
+}
+fn main () -> Result<(), Box<dyn std::error::Error>> {
+    let mut clips = ExampleClips(Arc::new(vec![].into()));
+    PoolClipCommand::Import(0, std::path::PathBuf::from("./example.mid")).execute(&mut clips)?;
+    Ok(())
+}