Improve/refactor outlets and view creation

[wagenet]

• lastRenderedTemplate should not get polluted - failing test case that shows how a route's lastRenderedTemplate can become polluted #3119
• template rendered into a named template should be able to use own outlet - A template rendered into a named template cannot use its own outlet #4434
• support rendering into an outlet created in a template render - Rendering into an outlet created in a template render fails #3626
• transition to static segment after dynamic should clean content - Transition to static segment after dynamic doesn't clear the content of outlet #3850
• avoid unnecessary view re-instantiation when changing model - Route view is initialized when model changes #4353

[ultimatemonty]

First off thanks for all you guys do in making Ember awesome!

Curious if there has been any progress on this front? The suggested work around from #3119 seems to be not as clean as hoped when using templates nested several levels deep. An example of my nesting is

this.route('module', function() {
   this.route('sub-module-1', function () {
      this.route('feature', function () {
         this.route('sub-feature');
      });
   });

   this.route('sub-module-2', function () {
      this.route('feature', function () {
         this.route('sub-feature');
      });
   });

   this.route('sub-module-3', function () {
      this.route('feature', function () {
         this.route('sub-feature');
      });
   });
});

In my case I'm seeing an issue where the template for a sub-module will not always clear out when transitioning to another sub-module at the same level.

[stefanpenner]

i think @ef4's recent work sorts most of this out.