Feature/copy exceptions

I was really tired of not being able to copy exceptions. This PR adds solid support for copying inline and console exceptions. Additionally, copying other content from the console should usually work, depending on what the element considers its text content to be.

A somewhat important structural change here is exposing the originating event to the menu+ behavior of objects that have had menu! triggered on them. This lets us use the existing menu+ behavior ( a single trigger on the entire ul.console) to handle copy requests for every console entry, rather than having to bind a listener to every entry.


Whoops, my bad. Being able to use the editor as a REPL has made me a lot more productive, but it also makes it easier to leave cruft from past experiments lying around. I'll need to investigate my diffs more closely before PRs.