Add adapter generator
Extract adapter definition from store.js to application_adapter.js
Merge pull request #415 from tricknotes/adapter-generator

Add adapter generator
Fetch modules for Ember.js with es6 syntax
Setup es6_module_transpiler-rails specified Ember app
Add base application supported by es6 modules
Remove type suffix from generated files

This commit changes generator's behavior, but doesn't break anything.
Support generator option `--javascript-engine=es6`
Add test for es6 module syntax
Update README.md to describe es6 module
Move adapter setting to adapters/application.*