HATop v0.8.1

This point release updates the backend F1/F2 hot keys so that they affect all instances of the backend, regardless of what frontend you are currently focused on. In most configurations, this is expected to be a noop, but in some edge cases, the actual desired behavior is to pull a node out of service. The legacy behavior has been moved to F9/F10. See #4 (and #5), and a big thank you to @tili41 for the legwork on landing this feature!