Fix the issue when hd_match.group(1) == false while hd_match.group(2) is None

[haoliang-quan]

So sorry for introducing the bug. The issue was, when hdUrl is set to false, hd_match.group(2) will still exist, but with the value None. In our old code, this will simply cause an exception and skip all the following logic for downloading a regular video. That means, the old code will only work for HD videos.

The fix first checks if hdUrl is false, if not, tries to download the HD video. Otherwise, still downloads the regular video.

[haoliang-quan]

@kyeolee89 please check if this fix the issue #12 .

[kyeolee89]

@hquan Thanks, And the 63th line does not contain line breaks in the regular expression, so it is not processed. You must modify it to include line breaks with the "re.DOTALL" option. Please Check it.