Update versions and display formatted tooltip

I updated the version in bower.json to match the tag on Github (0.0.8).

I bumped the seiyria-bootstrap-slider version from 3.1 to 4.2.

I changed the way the `formatter` (previously `formater`) argument is handled so that you can create tooltips like so:

```html
<slider ... formatter="{{ someScopeValue == 0 ? 'Nothing' : 'Value: ' + someScopeValue }}" />
``` 

I'm not sure if this is the best approach though. Perhaps it's better to refer to a function on the scope which also takes a `val` argument, like so:

```html
<slider ... formatter="theFormatter()" />
``` 

```js
scope.theFormatter = function(val) {
  val == 0 ? 'Nothing' : 'Value: ' + val
}
```

This would be more similar to the way seiyria-bootstrap-slider works, but I don't know how to achieve that.