At this stage the drag drop should only work in HTML5 compliant browsers
Displays a preview of the file if an image

Added styles to display a zone area to drop file (even though the whole page
is a drop zone)

Made the dropzone area show by default for compatible browsers and
have hidden the preview images. Added visual feedback to user for
dropping items in dropzone

Change-Id: I7a3104d7ded53f1c805779db86d407d2ec1aac26
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>