[removed] .js files from repo root

Also reorganized a few things:

index.js => modules/index.js
modules/helpers => modules/utils
script => scripts

Fixes #256
[changed] Use Browserify to build examples
[changed] Use Browserify to run specs
[removed] ActiveStore (yay!)

<Routes> components now store their own active state and emit active
state change events to ActiveState descendants that are interested.
This is a bit of a hack, but a major step forward for server-side
rendering.