fix(course_utils): encode all content when logging
fix(course_utils): encode all content when logging

also: do not encode sylabus_txt - this is unnecessary since the only
issue we have is when trying to log the whole content which in some
cases has mixed encodings (like the syllabus html).

This means that we can now display unicode/latin-1 characters in kodi
instead of removing them (with ignore)

MacHeathz/xbmc-coursera,cancan101/xbmc-coursera