Use `@import` instead of `//= require` in README.
Move assets to app/assets for compatibility with Rails 4.

Citing http://guides.rubyonrails.org/upgrading_ruby_on_rails.html#upgrading-from-rails-3-2-to-rails-4-0:
“In Rails 4.0, precompiling assets no longer automatically copies non-JS/CSS assets from vendor/assets and lib/assets. Rails application and engine developers should put these assets in app/assets.”
Bump version to 1.0.2