Replace _action_view with view_context to reflect that it is public and that it does not need to be an ActionView instance

	This is still not completely done and there might be pointers to things that don't exist yet.

Break up DependencyModule's dual function of providing a "depend_on" DSL and "included" block DSL into separate modules. But, unify both approaches under AS::Concern.

This reverts commit 0cac68d3.

Cleaned up the #render_to_body chain by extracting determining the templates to render to a separate hook point.

This reverts commit a747ab5b.

  * Decouple from ActionController and ActionMailer
  * Bring back localization support.
  * Prepare to decouple templates from the filesystem.
  * Prepare to decouple localization from ActionView
  * Fix ActionMailer to take advantage of ActionView::Path

Reinstate Base#render_to_string. Introduce AbstractController#render_to_string which stringifies render_to_body.

Rename render_to_string to render_to_body since it may return any Rack-compatible body, not just strings

* Required small architecture change

* Created several macros for writing simpler specs
* Finished making Rack::Test work right
* Implemented render_to_string
* Status Codes
* render :text => nil