Enable javadoc 'html' doclint

Also make all 'test' tasks depend on the 'javadoc' task.

Fixes SMACK-650.

smack-extensions/src/main/java/org/jivesoftware/smackx/filetransfer/FileTransferNegotiator.java

@@ -269,7 +269,7 @@ public final class FileTransferNegotiator extends Manager {
      * Send a request to another user to send them a file. The other user has
      * the option of, accepting, rejecting, or not responding to a received file
      * transfer request.
-     * <p/>
+     * <p>
      * If they accept, the stanza(/packet) will contain the other user's chosen stream
      * type to send the file across. The two choices this implementation
      * provides to the other user for file transfer are <a
@@ -277,11 +277,12 @@ public final class FileTransferNegotiator extends Manager {
      * which is the preferred method of transfer, and <a
      * href="http://www.xmpp.org/extensions/jep-0047.html">In-Band Bytestreams</a>,
      * which is the fallback mechanism.
-     * <p/>
+     * </p>
+     * <p>
      * The other user may choose to decline the file request if they do not
      * desire the file, their client does not support XEP-0096, or if there are
      * no acceptable means to transfer the file.
-     * <p/>
+     * </p>
      * Finally, if the other user does not respond this method will return null
      * after the specified timeout.
      *

smack-extensions/src/main/java/org/jivesoftware/smackx/filetransfer/FileTransferRequest.java

@@ -122,7 +122,7 @@ public class FileTransferRequest {
     /**
      * Accepts this file transfer and creates the incoming file transfer.
      * 
-     * @return Returns the <b><i>IncomingFileTransfer</b></i> on which the
+     * @return Returns the IncomingFileTransfer on which the
      *         file transfer can be carried out.
      */
     public IncomingFileTransfer accept() {

smack-extensions/src/main/java/org/jivesoftware/smackx/filetransfer/IncomingFileTransfer.java

@@ -42,12 +42,12 @@ import org.jivesoftware.smack.XMPPException.XMPPErrorException;
  * user on the jabber network. There are two stages of the file transfer to be
  * concerned with and they can be handled in different ways depending upon the
  * method that is invoked on this class.
- * <p/>
+ *
  * The first way that a file is recieved is by calling the
  * {@link #recieveFile()} method. This method, negotiates the appropriate stream
- * method and then returns the <b><i>InputStream</b></i> to read the file
+ * method and then returns the InputStream to read the file
  * data from.
- * <p/>
+ *
  * The second way that a file can be recieved through this class is by invoking
  * the {@link #recieveFile(File)} method. This method returns immediatly and
  * takes as its parameter a file on the local file system where the file
@@ -98,10 +98,10 @@ public class IncomingFileTransfer extends FileTransfer {
     /**
      * This method negotitates the stream and then transfer's the file over the negotiated stream.
      * The transfered file will be saved at the provided location.
-     * <p/>
+     *
      * This method will return immedialtly, file transfer progress can be monitored through several
      * methods:
-     * <p/>
+     *
      * <UL>
      * <LI>{@link FileTransfer#getStatus()}
      * <LI>{@link FileTransfer#getProgress()}