closes #6490

Squashed commits:

[ada0f09] Remove favorites from Posts table

closes #6208

deletes ActivityStream model and all it's references

update migration with the without_protection option to disable mass assignment protection

and tries to access a show page of a non-public post

This reverts commit c52342b7.

Lazily load post interactions on show page
hella refactorz

and comment presenter

clean up controller

include an iframe route, for posts, and a magic body padding removal for screens with small widths (for some reason, smaller than 770

Verify that the correct layout is rendered (rather than no layout
at all) in the mobile UI single post view.

This is a test I forgot to write at 5am when I was so excited about
having the mobile UI working on my Blackberry again (bad me!), so
here it is before it slips my mind. 😁

This tests the change made to posts_controller in 6abe7182

modified app to return a hash if current_user is not present; removed view specs in postsController specs & moved logic to js/jasmine

Delete all pending specs except stuff we actually want to fix in the short term. Add more useful comments to those.