Issue #26 Remove image trimmer chrome

Remove image trimmer apply, cancel, close buttons and title bar.
Issue #26 Add form elements above image trimmer

Add an input for URL and a button for uploading an image.
Issue #26 Link upload button to file uploader

Add event so that clicking on the 'upload' button triggers a file upload.
Issue #26 Show image from URL on blur

When blurring out of the URl input field, show the image in the trimmer
Issue #26 Clear url when upload is selected

Start tracking the source of the image in the controller.

Add a listener in the image trimmer choose view to clear the url
input field when source is not remote.
Issue #26 Make image parameters accessible by api

Remove image hidden input fields.

Catch all changes to image dimensions in a model on the top level controller.

Create api methods to get the image from the ImageTrimmer.

Have event form use this API instead of counting on DOM elements.
Issue #26 Save images by URL

Add a method to the event model to download images from a URL.

Add functionality to controller to process images from upload or URL.