Close all windows before ending the tutorial

+ TODO
Tutorial - exercise with moving target
Close all windows at the end of the tutorial automatically
Last impulse drive exercises
Merge pull request #5 from krzys-h/pull-tutorial2

Some more impulse drive exercises, end of basic tutorial
Added sci-fi font to the game
Prettier game explanation
fixed httpS link to fonts
Style fixes in pl.html
Implemented navigation using impulse drives
Adjusted speed factor
Added command 'manipulator attach'