Breaking changes

• Drop support to Sprockets < 3.

• Remove asset_digest helper a8d7cf7.

• config.assets.raise_runtime_errors is always enabled 655b93b.

  The option can be removed from config/environments/development.rb.

• config.assets.digest is enabled by default 3cb84ea.

• AssetFilteredError changes to AssetNotPrecompiled 059d470.

• Restricted default precompile to root app's own app/assets directory.

• Disable Rails.application.assets when compile = false #220.

New features

• Expose Rails.application.assets_manifest.
• Enable digest by default #221.
• Experimental SRI support #224