Adding missing imports for classes referenced in Javadoc
diff --git a/tapestry-core/src/main/java/org/apache/tapestry5/SymbolConstants.java b/tapestry-core/src/main/java/org/apache/tapestry5/SymbolConstants.java
index 899d6b8..07579c2 100644
--- a/tapestry-core/src/main/java/org/apache/tapestry5/SymbolConstants.java
+++ b/tapestry-core/src/main/java/org/apache/tapestry5/SymbolConstants.java
@@ -13,8 +13,11 @@
 package org.apache.tapestry5;
 
 import org.apache.tapestry5.corelib.base.AbstractField;
+import org.apache.tapestry5.corelib.components.AjaxFormLoop;
+import org.apache.tapestry5.corelib.components.BeanDisplay;
 import org.apache.tapestry5.corelib.components.BeanEditForm;
 import org.apache.tapestry5.corelib.components.BeanEditor;
+import org.apache.tapestry5.corelib.components.Errors;
 import org.apache.tapestry5.corelib.mixins.FormGroup;
 import org.apache.tapestry5.internal.services.AssetDispatcher;
 import org.apache.tapestry5.modules.NoBootstrapModule;