Rename ViewingTaggables to ViewingTagTaggings
Remove unused file
Rename ViewingTagTaggings to ViewingATagTaggings
Rename ViewingTaggableTaggings to ViewingATaggableTaggings
Styling improvements
Use the TaggingsPresenter in ViewingATagTaggings

* update the spec accordingly (viewing_a_tag_taggings_spec)
* Remove view files that are not needed anymore
* Update the spec for TagPresenter accordingly
* Update the feature spec for tag page accordingly
* Make the rendered table generic
	* TODO: hide the column which is unneeded depending on the context
Move associations from Tagging model to relevant contexts

* Move the belongs_to declaration to
  ViewingATagTaggings and ViewingATaggableTaggings
Use mocking in TaggingsPresenter for better spec isolation