start work on async execution
Merge branch 'master' into async-execution

Conflicts:
	src/app/mainwindow.cpp
new callback, test
Working version of async execution
Real-life async execution
Merge branch 'master' into async-execution

Conflicts:
	src/app/commandrunner.cpp
	src/app/commandrunner.h
	src/app/mainwindow.cpp
Merge branch 'async-execution'