Merge pull request #37 from peterasujan/gh-pages

Fixed issue involving topics-within-topics, made quiz styling prettier, added ability to hide stuff from topics.
adding a bunch of images, and fixing up "intro play" to use them
Merge branch 'gh-pages' of github.com:beautyjoy/bjc-r into gh-pages
converting 'different-ways-to-broadcast' to new assessment format, and
fixed a bit of formating on questions in css.
Merge pull request #41 from xtitter/gh-pages

images in intro play; fixing assessment in topic 1
removed exercise pages from end of topics
Can now hide videos/readings/etc from entire (or parts of) courses. See <div class='topic_container'> in berkeley_bjc.html for an example.
Topic pages now have link to their parent course at top of page. Curriculum pages have link to parent course in dropdown menu.