Refactor io.ebeaninternal.json.ModifyAwareOwner to io.ebean.ModifyAwareType

- Rename ModifyAwareOwner to ModifyAwareType
- Move to io.ebean (making it properly public)
- Remove the requirement for Serializable
- Simplify to effectively a getter/setter pair (dirty state flag)
- Simplify to reset the dirty state flag via

ebean-api/src/main/java/io/ebean/ModifyAwareType.java

@@ -0,0 +1,19 @@
+package io.ebean;
+
+/**
+ * Owner object notified when a modification is detected.
+ */
+public interface ModifyAwareType {
+
+  /**
+   * Return true if the value is considered dirty.
+   * Note that this resets the dirty status back to clean.
+   */
+  boolean isMarkedDirty();
+
+  /**
+   * Marks the object as modified.
+   */
+  void setMarkedDirty(boolean markedDirty);
+
+}