duplicate method id when multiple resources of different rax:roles share a method

This might also be related to issue #18. But my particular issue is related to when we combined all the various role-based WADLs we have into one single WADL using rax:roles. 

Our main WADL looks like this:
```
<application>
...
        <resource id="backup_events" path="backup/events" type="wadl/feed.wadl#AtomFeed wadl/feed.wadl#TenantAtomFeed wadl/product.wadl#CloudBackup"/>
...
</application>
```
The file ```wadl/feed.wadl``` contains:
```
<application>
...
    <resource_type id="AtomFeed">
        <resource id="service-admin" rax:roles="cloudfeeds:service-admin">
            <method href="#getFeed"/>
        </resource>
    </resource_type>
    <resource_type id="TenantAtomFeed">
        <resource id="observer" path="{tid}" rax:roles="cloudfeeds:observer">
            <param name="tid" type="xs:string" style="template"><doc>tenant ID</doc></param>
            <method href="#getFeed"/>
        </resource>
        ...
    </resource_type>
</application>

```
Notice that ```resource_type id="AtomFeed"``` and ```resource_type id="TenantAtomFeed"``` share a reference to ```method href="#getFeed```. 

The normalized WADL generates methods with duplicate ids: ```backup_events_getFeed```.

This PR attempts to fix it. For the most part, I got the correct method id generated in the normalized WADL:
```
<application>
...
         <resource xmlns:db="http://docbook.org/ns/docbook"
                   xmlns:wadl="http://wadl.dev.java.net/2009/02"
                   xmlns:error="http://docs.rackspace.com/core/error"
                   xmlns:event="http://docs.rackspace.com/core/event"
                   xmlns:usage-summary="http://docs.rackspace.com/core/usage-summary"
                   id="backup_events_service-admin_service-admin"
                   rax:roles="cloudfeeds:service-admin">
            <method name="GET" id="backup_events_service-admin_getFeed">
             ...
            </method>
            ...
         </resource>
...
```
But notice the resource id has "service-admin" duplicated. Can someone help me fix the resource id?

I've checked in the wadl to be normalized here: 
https://github.com/shintasmith/standard-usage-schemas/blob/B-65259_rax_roles/allfeeds.wadl