Adding Poster preview to poster.

* Adding preview iframe to Poster.show page.
* Adding Edit and Save buttons to Poster.show page.
* Redirecting users to Job.show page so they can add more posters.
* Removing posters coffeescript and adding posters javascript file.
* Formatting iframe.
* Creating a helper to link to poster temp url.
* Creating a poster model.
* Formatting jobs and posters views to match site flow model.
Adding Location to Workstation automatically.