Add circuit cross connect table/view

Implemented the "show connections" command to get information about circuit cross connects:
```
show connections | display xml rpc 
<rpc-reply xmlns:junos="http://xml.juniper.net/junos/12.3R6/junos">
    <rpc>
        <get-ccc-information>
        </get-ccc-information>
    </rpc>
    <cli>
        <banner>{master}</banner>
    </cli>
</rpc-reply>
```