Multiple grids on page with cardTemplateString use the last template available

http://plnkr.co/edit/SPdgpMOZzwYbDcBqN8pn?p=preview

```html
<div deckgrid source="[1,2,3]" cardTemplateString="aaa" class="deckgrid"></div>
<hr>
<div deckgrid source="[1,2,3,4]" cardTemplateString="bbb" class="deckgrid"></div>
<hr>
<div deckgrid source="[1,2,3,4,5,6,7]" cardTemplateString="ccc" class="deckgrid"></div>
<hr>
<div deckgrid source="[1,2,3,4,5,6,7,8]" cardTemplate="tpl1.html" class="deckgrid"></div>
<hr>
<div deckgrid source="[1,2,3,4,5,6,7,8]" cardTemplate="tpl2.html" class="deckgrid"></div>
<hr>
<div deckgrid source="[1,2,3,4,5,6,7]" cardTemplateString="ddd" class="deckgrid"></div>
```

Expected: templates aaa, bbb and ccc also displayed.
Actual result: all templates are ddd