[RFR] Configurable actions

View actions are now configurable:

```js
editView.actions(['show', 'list', 'delete']);
```

Alternately, if you pass a string, it is compiled just like an Angular template, with access to the current `entry` in the scope. This allows to easily add custom actions, or customize the buttons appearance:

```js
var template = '<show-button entry="entry" entity="posts" size="sm"></show-button>' +
                        '<delete-button entry="entry" entity="posts" size="sm"></delete-button>' +
                        '<my-custom-directive entry="entry"></my-custom-directive>' +
                        '<back-button></back-button>';
editView.actions(template);
```

The same logic has been applied to `listActions()` (API unchanged), which is now able to handle a template.