Fixes route matching issues

 modified:   config/routes.rb - this was already addressed in a5162c89, but somehow
              I messed it up during a commit squash/rebase
Removes test for Post.slug uniqueness as it is done with FriendlyId

 modified:   spec/models/post_spec.rb
Admin links are in lowercase now, specs should have been changed prior

 modified:   spec/requests/admin/session_pages_spec.rb
The app Home page is Posts#index so a spec for a static home page is pointless

 modified:   spec/requests/static_pages_spec.rb
Merge branch 'fix-specs' into develop-blog

These issues were overlooked when
  a) coding without running guard on the app specs
  b) messing up a merge conflict when commit squashing or rebasing
Migrates Post.status to Post.published_at

 new file:   db/migrate/20140101122053_rename_posts_status_to_published_at.rb
 modified:   db/schema.rb - modified the default value of published_at, which was defaulting
              to 'f' (should not have default value)
Updates Post model spec and factory for new field name

 modified:   spec/factories.rb
 modified:   spec/models/post_spec.rb
Updates Post admin controller views for new column name

 modified:   app/controllers/admin/posts_controller.rb
 modified:   app/views/admin/posts/_form.html.erb
 modified:   app/views/admin/posts/index.html.erb
 modified:   app/views/admin/posts/show.html.erb
Migrates the Post.published_at field from string to datetime

 new file:   db/migrate/20140101124026_change_posts_published_at_to_datetime.rb
              defines an up/down migration to change data from a string to datetime
 modified:   db/schema.rb
Modifies the Post factory to produce sequences of published_at values

 modified:   spec/factories.rb
Changes admin Post form `published_at` field to use a datetime select

 modified:   app/views/admin/posts/_form.html.erb
Adds an index on the Posts published_at field

 new file:   db/migrate/20140102055915_add_index_to_posts_published_at.rb
 modified:   db/schema.rb
Modifies Post factory to use traits for a draft and published Post

 modified:   spec/factories.rb
 modified:   spec/requests/post_pages_spec.rb
Increases requests specs for the public Post views to handle draft/published Posts

 modified:   spec/requests/post_pages_spec.rb
Creates a named scope in the Post model to return published Posts

 modified:   app/models/post.rb
Returns published Posts to the Post#index view

 modified:   app/controllers/posts_controller.rb
Updates the Post header partial for the new published_at field

 modified:   app/views/posts/_post_header.html.erb
Merge branch 'post-published-datetime' into develop-blog

 Migrates the Post `status` string field to `published_at` datetime field
 Updates Post model with a named scope published, which returns only
    published Posts
 Updates Post views and partials to display the new field
 Sspecs for the public Post views (to show draft/published posts)
Removes unused table that was commited to db/schema but not in any migrations
(probably from some random testing and it was overlooked)

 modified:   db/schema.rb
Migrates posts table to articles table as part of overall migration to a
single table inheritance schema

 new file:   db/migrate/20140108224943_change_posts_table_to_articles.rb
 modified:   db/schema.rb