Deal with overflowing tasks (start/end in previous/next weeks)
* Creates a differentiation when drawing a task that continues in other days not
  shown in the present view (their rectangles have an 'arrow' now)
* Centralizes the task title considering only the space on the present view
* Every task now is drawn using a rounded rectangle
Fix bug where tasks were still been referenced in next/previous weeks even though they were not drawn
Keep a task selected in order to edit or delete it.
* Not editing/deleting a random task anymore.
* If task is clicked, it will keep the focus, unless user clicks on 'empty' space