Allow multiple encoding formats apart from UTF-8

[timonoortman-aas]

Currently the algorithm only seems to accept SSIM files in UTF-8 encoding. In case of UTF-16, the following error is being raised:

With a small change, more formats should be accepted. E.g. by replacing

    with open(file, "r") as f:
        text = f.read()

in read(), by

import chardet
bytes = min(32, os.path.getsize(file))
raw = open(file, 'rb').read(bytes)
result = chardet.detect(raw)
encoding = result['encoding']
    with open(file, "r", ecoding=encoding) as f:
        text = f.read()