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 ok cool. Yea I like require because it allows you to load js when you actually need it instead of all the time. I could even possibly require the js and then assign a callback function that runs the code that uses it only after the file has actually been added to the page. This way you don't add more js then you ever need. Happy to hear other thoughts on this though!