Allow defining Queue Mode hooks multiple times (before_queue, after_subset_queue, after_queue)

[ArturT]

Allow defining multiple times hooks for Queue Mode like

• KnapsackPro::Hooks::Queue.before_queue
• KnapsackPro::Hooks::Queue.after_subset_queue
• KnapsackPro::Hooks::Queue.after_queue

why

So far you could define only once a hook for Queue Mode. This might be less convenient when you would like to keep hooks related code in a few separate files.

change

You can now define multiple times the same hook. Example:

KnapsackPro::Hooks::Queue.before_queue do
  puts '1st call'
end

KnapsackPro::Hooks::Queue.before_queue do
  puts '2nd call'
end

This works similarly to hooks in RSpec so you can define them many times.

Here are examples of using all hooks in Queue Mode:
https://github.com/KnapsackPro/knapsack_pro-ruby#what-hooks-are-supported-in-queue-mode