Introduced a field in SpringAMQPComponent to allow overriding default scheme

Hi guys, that's really a great job you've done there.
I had the need to address more than one broker in my app and in a dynamic way, so I thought the easiest way was to create and declare in camel context one SpringAMQPComponent (with its own connection factory) per broker instance and thus with its specific scheme (spring-amqp-xx:etc.) 
I then realized that Camel was using the endpoint#createEndpointUri wich was ignoring the specific scheme I had set preventing camel context to start because of falsy doubled endpoint definitions (see equals in DefaultEndpoint).
I would be glad if you could merge in my modifications or propose some other way to do it (overriding AmqpTemplate and Admin at endpoint level from uri maybe ?)
Regards.