Clean up make check rule
Add integration test for Runner

Temporarily increases tests duration by 1 second.

Conflicts:
	test/unit/runner.vala
Test Runner spawn failure
Extract Timer and CommandRunner from Runner
Test Timer
Test CommandRunner
Replace Runner integration test with isolated one
Pass game to Runner#run instead of constructor

We could expect the same configured runner to be used for successively running multiple games.
Rename Runner to GameRunner

To improve game/command runners distinction.

Conflicts:
	test/unit/runner.vala
Make GameRunner.testing constructor the default one

And rename the old one to *.with_defaults, to provide an easy migration path.
Extract Logger from CommandRunner and GameRunner
Extract Game#get_absolute_reference() from GameRunner
Move CommandRunner and Logger to utils/ subdir