Reportback modal cropping

*Links up the cropping functionality into the image upload modal and populates the main reportback form with the cropping coordinates.

*Moved cropping interface styles to the crop modal sass.

@weerd 

@weerd sure i will try renaming some stuff. For this one it is interesting because it is actually acting like a container since the main purpose of this div is to create a bounding box for cropping. Maybe I can make it `.crop-bounding-box` or something.