fix #8 pipeline could not be saved correctly

The issue is caused by failure on serialize/deserialize of interfaces.
Now use AbstractCollection to specify implementations manually.

Author: lotabout

resources/META-INF/plugin.xml

@@ -1,7 +1,7 @@
 <idea-plugin>
   <id>me.lotabout.codegenerator</id>
   <name>Code Generator</name>
-  <version>1.3.2</version>
+  <version>1.3.3</version>
   <vendor email="lotabout@gmail.com" url="https://lotabout.me">Jinzhou Zhang</vendor>
 
   <description><![CDATA[
@@ -20,6 +20,7 @@
 
   <change-notes><![CDATA[
   <ul>
+  <li>version 1.3.3 <p>fix: pipeline settings could not be saved.</p></li>
   <li>version 1.3.2 <p>support idea 2016.3 and after</p></li>
   <li>version 1.3.1 <p>move Code Generator Menu to Generate menu</p></li>
   <li>version 1.3 <p>support insert at caret. Fix bugs</p></li>

src/me/lotabout/codegenerator/config/CodeTemplate.java

@@ -1,6 +1,8 @@
 package me.lotabout.codegenerator.config;
 
 import com.intellij.openapi.util.io.FileUtil;
+import com.intellij.util.xmlb.annotations.AbstractCollection;
+
 import org.apache.commons.lang.builder.EqualsBuilder;
 import org.apache.commons.lang.builder.HashCodeBuilder;
 import org.jetbrains.java.generate.config.DuplicationPolicy;
@@ -30,6 +32,7 @@ public class CodeTemplate {
             @XmlElement(name="classSelection", type=ClassSelectionConfig.class)
     })
     @XmlElementWrapper
+    @AbstractCollection(elementTypes = {MemberSelectionConfig.class, ClassSelectionConfig.class})
     public List<PipelineStep> pipeline = new ArrayList<>();
 
     public InsertWhere insertNewMethodOption = InsertWhere.AT_CARET;