Browserify v3

Update various dev dependencies and build process.
- Some basic browserify dependent module substitutions such as
  coffeeify for caching-coffeeify.
- Reworked plugin loader into a browserify plugin. This can probably
  be evolved further to a nice pattern for namespace plugins to
  browserify from the CLI. Maybe a separate module. The reason it had
  to be in this change is that watchify with browserify v3 tries errors
  dealing with the stream input, which makes sense.
- Fixes build warnings with watchify
Log pack failures during build
Support inter-plugin dependencies