Merge pull request #15 from olga-jane/master

update from origin
Merge pull request #17 from olga-jane/master

Merge from olga-jane/master
add handler on exit actions (alt+f4, from menu and close button)
Fix application closing on alt+f4 and close button
Merge pull request #633 from qlynn/sborsuk_exit

Program should exit fully and correctly [8]