QueryElevationComponent

[Grant Ingersoll <gs...@apache.org>]

In the QueryElevComponent (QEC) it currently throws an exception if  
the input Query is null (line 329).    Additionally, I've seen cases  
where it's possible that the Query is not null (q is not set, but  
q.alt is *:*), but the rb.getQueryString() is null, which causes an  
NPE on line 300 or so.

I'd like to suggest that if the Query is empty/null, the QEC should  
just go on it's merry way as if there is nothing to do.  I don't think  
a lack of query means that the QEC is improperly configured, as the  
exception message implies:
	The QueryElevationComponent needs to be registered 'after' the query  
component

We should be making sure the QEC is properly registered during  
initialization time.

Thoughts?

-Grant