No easy way of documenting events

[mbrio]

Looking through Atom and Biscotto I couldn't find any examples of documenting emitted events and felt this was a weakness of Biscotto/TomDoc. Since Biscotto has other extensions I propose adding an Emits keyword:

# Emits loaded whenever something is loaded. The first argument will be an
#   {Object} and the second argument will be a {Boolean}