upgrade pyramid_webassets for url_expire option

This is very useful for things like extension development where the
embed code needs to be rebuilt rarely (only when asset bundles or the
embed code itself changes), but leaving cache busting query strings
in the URLs it loads from means the extension must be rebuilt whenever
any code in an asset bundle changes.

Using 22d68031eadc417c88796b63bf72e87deb8abd6b from my fork until
the pull request is merged.

Other changes have to do with the fact that pyramid_webassets doesn't
add the static routes automatically anymore. Therefore, we do in our
assets.py. I also changed the development setup to not use versioned
URLs and to use "assets" instead of "static" as an output directory
and URL prefix for built assets, because I decided I like it so there.
fix jschannel bundle output
remove unnecessary deform reference in layout
noConflict loading

- Use noConflict for Annotator and jQuery after loading.
- window.Annotator becomes window.annotator, which is the instance
  rather than the constructor. Host pages should not need to
  construct their own Annotator directly. This is one change toward
  re-imagining annotator as a DOM API.
- Closes #12