Add Life variants

[peterhellberg]

Add some of the variants from A selection of Life-like rules

Possibly by writing a parser for the rule short hand format.

Quick and dirty example:

    for y := 0; y < h; y++ {
        for x := 0; x < w; x++ {
            n := aliveNeighbours(x, y)

            if isAlive(x, y) {
                aliveCells++

                //if n < 2 || n > 3 { // Game of Life
                //if !(n == 3 || n == 4 || n == 6 || n == 7 || n == 8) { // Day & Night
                // if !(n == 2 || n == 3) { // HighLife
                killList = append(killList, Point{x, y})
                //}
            } else {
                //if n == 3 { // Game of Life
                //if n == 3 || n == 6 || n == 7 || n == 8 { // Day & Night
                // if n == 3 || n == 6 { // HighLife
                if n == 2 { // Seed
                    spawnList = append(spawnList, Point{x, y})
                }
            }
        }
    }