Interact js

[DimitarChristoff]

removal of jquery-ui, event.drag, adding interact.js

still broken: a bunch of calls on drag events on canvas that bubble:

      $canvas
        .bind('keydown', handleKeyDown)
        .bind('click', handleClick)
        .bind('dblclick', handleDblClick)
        .bind('contextmenu', handleContextMenu)
        .bind('draginit', handleDragInit)
        .bind('dragstart', {distance: 3}, handleDragStart)
        .bind('drag', handleDrag)
        .bind('dragend', handleDragEnd)