Issue #15: Handle non-text files better
Issue #15: Handle non-text files better

I added an exception handler in findSourceFromHTML() in case the URL
ends up redirecting to a non-text file. This is to handle e.g. imgur
.gifv links which are removed (imgur auto redirects to removed.png)

makuto/redditLikedSavedImageDownloader,makuto/redditLikedSavedImageDownloader,makuto/redditLikedSavedImageDownloader