Code review feedback incorporation

- Changed Qtrix#queues_for! to Qtrix#fetch_queues
- Cap size of weightings to ensure all queues at head of 1 list.
- Ensure no duplicate queues in any rows of the matrix
- Ensure qtrix queues -l can target config-sets.
- Let people use qtrix config-sets as an alias for config_sets
- numeric.times used instead of (1..numeric) for a loop