Added twitter bootstrap3 translated view, fixed a duplicate service id name in pagerfanta.xml

Hi,

Thanks for adding twitter bootstrap3 support, but since i needed the translated version i decided to add this.

I think i also fixed a bug in pagerfanta.xml
There are two identical named service id's pointing to different classes...
```xml
<!-- "twitter_bootstrap" view -->
        <service id="pagerfanta.view.twitter_bootstrap" class="Pagerfanta\View\TwitterBootstrapView" public="false">
            <tag name="pagerfanta.view" alias="twitter_bootstrap" />
        </service>

        <!-- "twitter_bootstrap3" view -->
        <service id="pagerfanta.view.twitter_bootstrap" class="Pagerfanta\View\TwitterBootstrap3View" public="false">
            <tag name="pagerfanta.view" alias="twitter_bootstrap3" />
        </service>
```