Fixed comments
Added some utility function for the slides viewport
Added the incremental effect. Created the duplicate slide tool.
Implementation of a 'hide/show slide' tool
Changes done by hide/show tool are now taken into account by the undo/redo tool
Disabled the video item
Added the placeholder widget for the transition tool and implemention of the required programming interface
Fixed the file system reference on image drop in the dropzonefilter
It is now possible to resize images using the square at the top right of an image.
Preview now correctly applies width and heights of resized images
Changed the behavior of the resize handle. The resizing now keeps the original w/h ratio of the image. Free resizing is implemented but not used for now.
Moved the code for resizing