Add initializer tests and move classpath files

The initializer tests verify that every non-optional initializer, this
includes Providers, is loadable.

Creating files under META-INF is not considered best practice. Smack's
configuration and provider files reside now in classpath directory
qualified by Smack's package namespace.

extensions/src/main/java/org/jivesoftware/smackx/ExtensionInitializer.java

@@ -1,16 +0,0 @@
-package org.jivesoftware.smackx;
-
-import org.jivesoftware.smack.provider.UrlProviderFileInitializer;
-
-/**
- * Loads the default provider file for the Smack extensions on initialization.
- * 
- * @author Robin Collier
- *
- */
-public class ExtensionInitializer extends UrlProviderFileInitializer {
-    @Override
-    protected String getFilePath() {
-        return "classpath:META-INF/extension.providers";
-    }
-}

extensions/src/main/java/org/jivesoftware/smackx/ExtensionsProviderInitializer.java

@@ -0,0 +1,16 @@
+package org.jivesoftware.smackx;
+
+import org.jivesoftware.smack.initializer.UrlProviderFileInitializer;
+
+/**
+ * Loads the default provider file for the Smack extensions on initialization.
+ * 
+ * @author Robin Collier
+ *
+ */
+public class ExtensionsProviderInitializer extends UrlProviderFileInitializer {
+    @Override
+    protected String getFilePath() {
+        return "classpath:org.jivesoftware.smackx/extensions.providers";
+    }
+}

extensions/src/main/java/org/jivesoftware/smackx/ExtensionsStartupClasses.java

@@ -0,0 +1,65 @@
+package org.jivesoftware.smackx;
+
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.jivesoftware.smack.SmackConfiguration;
+import org.jivesoftware.smack.initializer.SmackInitializer;
+import org.jivesoftware.smack.util.FileUtils;
+import org.xmlpull.mxp1.MXParser;
+import org.xmlpull.v1.XmlPullParser;
+
+public class ExtensionsStartupClasses implements SmackInitializer {
+
+    private static final String EXTENSIONS_XML = "classpath:org.jivesoftware.smackx/extensions.xml";
+
+    private List<Exception> exceptions = new LinkedList<Exception>();
+    // TODO log
+
+    @Override
+    public void initialize() {
+        InputStream is;
+        XmlPullParser parser;
+        int eventType;
+        try {
+            is = FileUtils.getStreamForUrl(EXTENSIONS_XML, null);
+            parser = new MXParser();
+            parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
+            parser.setInput(is, "UTF-8");
+            eventType = parser.getEventType();
+        }
+        catch (Exception e) {
+            exceptions.add(e);
+            return;
+        }
+        try {
+            do {
+                String name = parser.getName();
+                if (eventType == XmlPullParser.START_TAG) {
+                    if ("startupClasses".equals(name)) {
+                        try {
+                            SmackConfiguration.parseClassesToLoad(parser, false);
+                        }
+                        catch (Exception e) {
+                            exceptions.add(e);
+                        }
+                    }
+                }
+                eventType = parser.next();
+            }
+            while (eventType != XmlPullParser.END_DOCUMENT);
+            is.close();
+        }
+        catch (Exception e) {
+            exceptions.add(e);
+        }
+    }
+
+    @Override
+    public List<Exception> getExceptions() {
+        return Collections.unmodifiableList(exceptions);
+    }
+
+}