Add the ability to create queues with attributes

[paraseba]

Now mk-connection takes optional keyword arguments

:queue-attributes and :dead-letter-queue-attributes

These are maps from string to string with SQS attribute names and values.

This is a non breaking change, users of previous versions of the library don't need to modify their code to upgrade.

[aykuznetsova]

Looks good to me!

[ghost]

LGTM