Allow interactive mode to be used with concurrency

[lindell]

Currently, interactive mode can't be activated at the same time as concurrency > 1.

This would be beneficial since while manually looking at some changes, MG could look for new ones.

To archive, this, locking of the interactive part has to take place, and any logging during this time has to be suspended (at least when writing to stdout) and then resumed when the user is no longer making decisions.

Some more discussion around this was held in the issue around creating the interactive mode #123