Expose non-AST item state (isFrozen and isSendState).

- Report those states in REST API

eraser-base/src/main/jastadd/Item.jrag

@@ -6,10 +6,12 @@ aspect ItemHandling {
   protected boolean Item.isFrozen = false;
   public void Item.freeze() { isFrozen = true; }
   public void Item.unfreeze() { isFrozen = false; }
+  public final boolean Item.isFrozen() { return isFrozen; }
 
   protected boolean Item.sendState = true;
   public void Item.disableSendState() { sendState = false; }
   public void Item.enableSendState() { sendState = true; }
+  public final boolean Item.isSendState() { return sendState; }
 
   //--- getStateAsString ---
   syn String Item.getStateAsString();

eraser.spark/src/main/java/de/tudresden/inf/st/eraser/spark/Application.java

@@ -182,6 +182,8 @@ public class Application {
     return SimpleItem.of(item.getID(),
         item.getLabel(),
         item.getTopic() != null ? item.getTopic().allParts() : null,
+        item.isFrozen(),
+        item.isSendState(),
         item.getControllingList().stream().map(Item::getID).collect(Collectors.toList()),
         wrapMetaData(item.getMetaDataList()));
   }

eraser.spark/src/main/java/de/tudresden/inf/st/eraser/spark/SimpleItem.java

@@ -15,6 +15,8 @@ public class SimpleItem {
   public final String ID;
   public final String label;
   public final String topic;
+  public final boolean frozen;
+  public final boolean sendState;
   public final List<String> controlling;
   public final Map<String, String> metaData;
 }