add current() method to get the current acquisition

src/main/java/org/micromanager/lightsheetmanager/api/AcquisitionManager.java

@@ -1,9 +1,20 @@
 package org.micromanager.lightsheetmanager.api;
 
+import org.micromanager.acqj.main.Acquisition;
+
 import java.util.concurrent.Future;
 
 public interface AcquisitionManager {
 
+    /**
+     * Return the acquisition currently being set up or running.
+     *
+     * @return the current acquisition, or null. Null before setup constructs it and again
+     *         once the run finishes. Callers needing it after the run, for example to call
+     *         checkForExceptions(), must retain their own reference.
+     */
+    Acquisition current();
+
     /**
      * Request that an acquisition is run.
      *

src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngine.java

@@ -487,6 +487,11 @@ public AutofocusAdapter autofocus() {
         return autofocus_;
     }
 
+    @Override
+    public Acquisition current() {
+        return currentAcquisition_;
+    }
+
 //////////////////////// AcquisitionControl Callback methods ////////////////////////
     @Override
     public void stop(boolean interrupted) {