Fix staff markers for inline threads and double staff markers for threads with deeply nested comments.

It worked in Chrome because Chrome appears to magically infer some missing
arguments to methods. This is the second time this happened, should be more
careful about it in the future, because it causes confusion when features
work for some students but not others.

following if it wasn't working before.

Fix WMD editor reply boxes on embedded discussions, although I think the way it's implemented is something of a hack.

Needs different CSS to make it more appropriate in the embedded view.