Rewrite browserify config

New plan is to attempt to make a single browserify
bundle of JS + Coffee and app + vendor. 

Thoughts:
* We'd remove concat_sourcemap if we could, but other plugins will want
to use it (conflicts) and we also want our global JST/templates to come
along.
* concat_sourcemap chokes on the sourcemaps from browserify, which are
provided as Data URIs. Can it be changed on either side to fix this? #7
* How do we provide multiple basepaths so vendor stuff can be loaded?