find datafile and load them from codec
    TODO only does the first one
    kwargs:
    default = if passed will return that on failure instead of throwing

def load_datafile(name, search_path=('.'), codecs=get_codecs(), **kwargs):
    """
    find datafile and load them from codec
    TODO only does the first one
    kwargs:
    default = if passed will return that on failure instead of throwing
    """
    mod = find_datafile(name, search_path, codecs)
    if not mod:
        if 'default' in kwargs:
            return kwargs['default']
        raise IOError("file %s not found in search path %s" %(name, str(search_path)))

    (codec, datafile) = mod[0]
    return codec().load(open(datafile))