Add clear screen support

[x1unix]

The official Go Playground has a Game of Life demo which uses \x0c escape symbol to clear the screen.

Research possibility of clear screen support.

[x1unix]

The playground is switching to XTerm library which supports most POSIX terminal escape sequences.

The only thing is that \x0c is not a clear screen but FF (form feed) character. I'll provide a different snippet with a correct character - \x1Bc.