eliminate unsafe, unescaped injection of user-generated content
Nest a new Comment form inside TodosShow BB view

Instantiating a view in #render is bad!
fix mispelled event

Exists from 5b1efcd09df086252152161d48e4844c714504a6
include Marked library
implement Markdown preview for CommentsNew BB view
be very careful to escape UGC before passing to marked