Move all js files to js/ directory

and move a css file to css/ directory.
Create misc directory

Move patches, configs, scripts and some other files except
runtime files to misc directory.
Fix image paths
Add simple http server script

To escape protections for local storages in Chrome,
we introduce a simple http server. Usage:
  ruby misc/simple-http-server.rb
and access http://localhost:8080/arm-js.html.