webexercises 1.1.0

• quarto support (create_quarto_doc() and add_to_quarto())
• fenced .webex-check sections for self-checking quizzes
• webex.hide knit hooks get set up .onLoad instead of in webex.R
• remove js dependency on jquery
• total_correct() deprecated
• PDF rendering is better (but webexercises is really built for HTML)