Check from GitHub slpkg repository if new version is available
    download and update itself

def it_self_update():
    """Check from GitHub slpkg repository if new version is available
    download and update itself
    """
    __new_version__ = ""
    repository = "gitlab"
    branch = "master"
    ver_link = ("https://raw.{0}usercontent.com/{1}/{2}/"
                "{3}/{4}/__metadata__.py".format(repository, _meta_.__author__,
                                                 _meta_.__all__, branch,
                                                 _meta_.__all__))
    version_data = URL(ver_link).reading()
    for line in version_data.splitlines():
        line = line.strip()
        if line.startswith("__version_info__"):
            __new_version__ = ".".join(re.findall(r"\d+", line))
    if __new_version__ > _meta_.__version__:
        if _meta_.default_answer in ["y", "Y"]:
            answer = _meta_.default_answer
        else:
            print("\nNew version '{0}-{1}' is available !\n".format(
                _meta_.__all__, __new_version__))
            try:
                answer = raw_input("Would you like to upgrade [y/N]? ")
            except EOFError:
                print("")
                raise SystemExit()
        if answer in ["y", "Y"]:
            print("")   # new line after answer
        else:
            raise SystemExit()
        dwn_link = ["https://{0}.com/{1}/{2}/archive/"
                    "v{3}/{4}-{5}.tar.gz".format(repository, _meta_.__author__,
                                                 _meta_.__all__,
                                                 __new_version__,
                                                 _meta_.__all__,
                                                 __new_version__)]
        if not os.path.exists(_meta_.build_path):
            os.makedirs(_meta_.build_path)
        Download(_meta_.build_path, dwn_link, repo="").start()
        os.chdir(_meta_.build_path)
        slpkg_tar_file = "slpkg" + "-" + __new_version__ + ".tar.gz"
        tar = tarfile.open(slpkg_tar_file)
        tar.extractall()
        tar.close()
        file_name = "{0}-{1}".format(_meta_.__all__, __new_version__)
        os.chdir(file_name)
        check_md5(pkg_checksum(slpkg_tar_file, _meta_.__all__),
                  _meta_.build_path + slpkg_tar_file)
        subprocess.call("chmod +x {0}".format("install.sh"), shell=True)
        subprocess.call("sh install.sh", shell=True)
    else:
        print("\n{0}: There is no new version, already used the last !"
              "\n".format(_meta_.__all__))
    raise SystemExit()