fix pipe_ignore has effect on sending message

[metheoryt]

fix issue when pipe_ignore has effect on sending message instead if receiving, as it described in documentation https://dramatiq.io/cookbook.html#pipelines

[Bogdanp]

Thanks! Please add a test for this and don't forget to add yourself to CONTRIBUTORS.md.

[metheoryt]

I need some clarification about actor whose messages gets piped - should he be declared with store_result=True to be able to receive message result as argument or this feature is enabled as long as dramatiq has result backend?

UPD figured it out, store_result does not affect argument passing, only result fetching

[Bogdanp]

Thanks again! This is merged with rebase and will be released soon.