Allow resizing from top and left edges in addition to bottom and right

```javascript
interact(target).resizable({
  edges: {
    top: true,
    left: true,
    bottom: true,
    right: true
  },  
  edgeSelectors: {
    top: '.resize-n',
    left: '.resize-w',
    bottom: 'resize-s',
    right: 'resize-e'
  }
});
```

Closes #37