refactor(menu): inject MenuController to control app menus

Menu has been improved to make it easier to open, close, toggle and
enable menus.
Instead of injecting `IonicApp` to find the menu component, you now
inject
`MenuController`.

Was:

```
constructor(app: IonicApp) {
  this.app = app;
}
openMenu() {
  this.app.getComponent('leftMenu').close();
}
```

Now:

To programmatically interact with any menu, you can inject the
`MenuController`
provider into any component or directive. This makes it easy get ahold
of and
control the correct menu instance. By default Ionic will find the app's
menu
without requiring a menu ID. An id attribute on an `<ion-menu>` is only
required
if there are multiple menus on the same side. If there are multiple
menus, but
on different sides, you can use the name of the side to get the correct
menu

If there's only one menu:

```
constructor(menu: MenuController) {
  this.menu = menu;
}
openMenu() {
  this.menu.close();
}
```

If there is a menu on the left and right side:

```
toggleMenu() {
  this.menu.toggle('left');
}
```

If there are multiple menus on the same side:

```
<ion-menu id="myMenuId" side="left">...</ion-menu>
<ion-menu id="otherMenuId" side="left">...</ion-menu>

closeMenu() {
  this.menu.close('myMenuId');
}
```

ionic/components.ts

@@ -10,6 +10,7 @@ export * from './components/icon/icon'
 export * from './components/input/input'
 export * from './components/item/item'
 export * from './components/item/item-sliding'
+export * from './components/menu/menu-controller'
 export * from './components/menu/menu'
 export * from './components/menu/menu-types'
 export * from './components/menu/menu-toggle'