Issue #26 Image trimmer to manage one instance

Image trimmer had been configured to manage a series of instances. Change this
so now the image trimmer can only manage one instance of itself.
Issue #26 Privatize catch methods

Methods for catching image position and size in the image trimmer have been privatized.
These methods should not be callable from outside the image trimmer.
Issue #26 Remove extra function for showing dialog

There was a function in the image trimmer dedicated to showing the dialog.
Remove this because the dialog will always be shown at render now.
Issue #26 Link image parameter changes to catch

Use new private catch methods in change image event callbacks.
Issue #26 Create test case for showing image

When an image is loaded from a URL it should appear in the image trimmer.
Add a test case to verify this.
Issue #26 Add logic to reject bad files

Only images can be loaded into the image trimmer. Create a list of valid files
and add logic to reject invalid files.
Issue #26 Conceal new image method

Method should only be called by new:image event.
Issue #26 Include application css file in spec

Application css file now appears in the spec so that the image trimmer
can take on its required characteristics.
Issue #26 Add test case for placing an image

When an image is loaded it should be placed in the center of the image trim.
Add a test case to verify this.
Issue #26 Test case for images that are not 4x3

Add a test case that verifies that a non 4x3 image will fit properly when
loaded.
Issue #26 Add test case for loading long images
Issue #26 Disable save on click and add a message

When the save button is clicked, disable it so it wont be clicked again
then add a message.
Issue #26 Basic error handling for bad images

When a URL or image is entered that cannot be handled, clear the previous
image and do not proceed.