Update Input- and OutputInterface on cached Manager

[moritz-h]

Fix: #960
The commands get a fresh InputInterface and OutputInterface Instance for each time, the command runs. But the commands cache the Manager instance, which gets a reference to the Input/OutputInterface on construction. So when the command runs a second time, they get fresh Input/OutputInterfaces but uses the cached Manager Instance with reference to old Input/OutputInterface Instances.
This PR updates the Input and OutputInterface of the cached Manager to the Input/OutputInterface of the current command run. (See #960 comment for more details)

[rquadling]

That makes sense to me. Can you write a test that proves getting the manager gets the injected Input/Output.

[moritz-h]

I thougth of writing a test for this and read througth your tests. I wanted to start here:
https://github.com/robmorgan/phinx/blob/v0.8.0/tests/Phinx/Console/Command/StatusTest.php

I saw you are using a manager stub in the tests and my idea was to test somehow if the stub gets the new input/output Interfaces on command execution. But i don't find any code where you are testing the bootstrap part of a command. So i had no startpoint where i could add these tests.
If you can give me a hint where i could add these tests, i will try to write some.

[piotr-cz]

Thanks, this fixed the issue