More consistence of whether to expect a model or collection

[enov]

To enhance the protected find_mode function, and be consistent of whether to return model or collection.

I think it is always good to return a collection, unless of very specific reasons where the developers expects or knows that Aurora will return a model. Those reasons can be summarized by the following:

• The developer feeds a new model that should be retrieved.
• The developer asks for model 'Model_Common_Name' see issue No 3
• The developer feeds a scalar $params to load()

We should remove logic where Aurora tests for number of rows returned.