add getUser(username) and getProject(projectName) method

[zacker330]

 // new method
 public GitlabProject getProject(String NAMESPACE_PROJECT_NAME) throws IOException {
    String tailUrl = GitlabProject.URL + "/" + NAMESPACE_PROJECT_NAME;
    return retrieve().to(tailUrl, GitlabProject.class);
  }

// new method
public GitlabUser getUser(String username) throws IOException {
    String tailUrl = GitlabUser.URL + "?search=" + username;
    GitlabUser[] arrays = retrieve().to(tailUrl, GitlabUser[].class);
    if (null == arrays || arrays.length == 0) return null;
    return arrays[0];
}

[timols]

@zacker330 I'd like to merge this in but it seems that it won't merge cleanly. Would you mind resolving the merge issues and update your pull request?

[bitsofinfo]

Can this get merged please?

[timols]

@bitsofinfo happy to but I'm hoping @zacker330 would mind resolving the merge conflicts so I can merge it in.

[gustavolira]

I'd make a contribution to add createUser(GitlabUser user, String password) and createProject(GitlabProject project) but I see this pull requests and it is exactly what I would do.
There is any prevision when this pull request will be add to this project?

[zacker330]

@timols I'm sorry for missing this message for long time. And I forget the logic of this project cause by I have long time not work on it.

I just added two methods, maybe you can add those by yourself straightly.