TerminatorCore requires xdotool.
This overrides the default setting of Konsole core and capture on Linux, if the "terminator" binary is found in PATH.
Couple of gotchas: * only works if the active window at the start of any invocation is a terminator window, and all commands operate on that, and * requires the "xdotool" utility to be in the path.
Basic structure aped from Konsole core tests.
Just and empty implementation for now.
This allows using watchr to run the tests on e.g. Linux.