select bottom of new split (for easy deletion)

src/main/mesh.js

@@ -201,6 +201,7 @@ let split = {
         let { models, plane, zlist } = split.state;
         log.emit(`splitting ${models.length} model(s) at ${plane.z.round(3)}`).pin();
         Promise.all(models.map(m => m.split(plane))).then(models => {
+            mesh.api.selection.set(models);
             log.emit('split complete').unpin();
             split.end();
         });

src/mesh/model.js

@@ -357,14 +357,14 @@ mesh.model = class MeshModel extends mesh.object {
                     file: `${this.file}`,
                     mesh: o2
                 }).applyMatrix4(m4)).select();
-                // this becomes bottom
                 if (o1.length) {
+                    // this becomes bottom
                     this.reload(o1);
+                    resolve(this);
                 } else {
                     this.remove();
+                    resolve(model);
                 }
-                // return the split model
-                resolve(model);
             });
         });
     }