Break apart AMD and CommonJS again

Just this simple change and everything is great!

Convert annotator for r.js:

  $ npm install annotator
  $ r.js -convert node_modules/annotator annotator

Then include annotator in a `packages` configuration and require away!

Due to the browser field in package.json, browserify still works fine, too.
Fix relative paths in source maps
Stop require()'ing / exporting jquery

Just go back to getting it from the environment. It is up to the
packager to get the proper $ into scope when requiring annotator.

Plugins should be loaded in the same environment and not expect
to get `Annotator.$`.
Add empty .npmignore to lib so it gets packed
Remove unused dependency on through
Make sure all things needed are copied to pkg/
Make sure the pkg/lib dir exists
Output build directly to /pkg/lib is created
Rework amd, browserify, and npm interfaces

This (re?-)introduces namespace.coffee. Briefly, it allows plugins
to enhance Annotator through global extension or AMD injection.
Fix double promise rejection in build system