v0.6.0

• Use system-level tee to pipe STDOUT to both STDOUT and the logs. #351
• Invoke EmberCli[ember_app].build from helpers to ensure everything is built
  before serving. #347
• Remove dependency on sprockets. Serve generated files with Rack::File.
  #336
• Rename generator namespace from ember-cli to ember. #344
• Ensure Rails.root.join("log") exists when writing to logs.
• Remove deprecated include_ember_index_html helper and deprecated
  build_timeout and enabled configurations. #334
• Raise build errors for render_ember_app failures. #325
• Remove before_{action,filter} in favor of explicit EmberCli.build(app)
  call. #327