getUserDetail() method always throws NullPointerException.
There is even no testcase for the method.

The following test method will reproduce the issue:
-------
    public void testGetUserDetail() throws Exception{
        UserWithStatus uws = twitterAPI1.getUserDetail(id1);
        assertEquals(id1, uws.getId());
    }
-------

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java.lang.NullPointerException
at twitter4j.TwitterResponse.ensureRootNodeNameIs(TwitterResponse.java:20)
at twitter4j.User.<init>(User.java:17)
at twitter4j.Status.<init>(Status.java:18)
at twitter4j.UserWithStatus.<init>(UserWithStatus.java:11)
at twitter4j.Twitter.getUserDetail(Twitter.java:311)
at twitter4j.TwitterTestUnit.testGetUserDetail(TwitterTestUnit.java:83)
-----------