* Do not accept '>' between the property and content attributes.
* Recognize the properties if the content attribute is before the property attribute using two regexes (fixes the extraction of the description for SlideshareIE).
Makes writeinfojson behaving exactly as writethumbnail in case where filename contains mediafile extension.
Case:
video.mp4 converted to music.mp3 would yield music.mp4.info.json instead music.mp3.info.json or music.info.json