Load variables from environment variables.

def load_variables():
    """Load variables from environment variables."""
    if (not os.environ.get("PYCONFLUENCE_TOKEN") or
            not os.environ.get("PYCONFLUENCE_USER") or
            not os.environ.get("PYCONFLUENCE_ORG")):
        print ("One or more pyconfluence environment variables are not set. "
               "See README for directions on how to resolve this.")
        sys.exit("Error")

    global token
    global user
    global base_url
    token = os.environ["PYCONFLUENCE_TOKEN"]
    user = os.environ["PYCONFLUENCE_USER"]
    base_url = ("https://" + os.environ["PYCONFLUENCE_ORG"] + ".atlassian"
                ".net/wiki/rest/api/content")