Autoselection and resize for slide creation.

Added functionality to select widget on canvas to put it into focus. Click the widget desired and it will be brought to focus. Previously widgets must be selected via selecting them in the left menu list. Now you can change focus within the canvas.

In-canvas size changer added so that widgets in focus can have their resize done on the canvas. A resize indicator now exists on a widget that is in selection in the bottom right corner. Click and drag to be able to resize as long as it is within the canvas bounds.