relaxed failure limit

[khrome]

This takes it from failing about half the time to failing less than ~5% of the time (anecdotally) while retaining performance.

[Marak]

LGTM. Thank you for your contribution.

In the production demo we are infinitely retrying in a loop using new random seed:

  function tryGenerate(generatorType, map) {
    try {
      generators[generatorType](map, {});
      if (LABY.terrains[generatorType]) {
        map.scaleToTileRange(4);
      }
      updateMapDisplay(map);
    } catch (err) {
      // console.log(err)
      //console.log('try again');
      map.seedRandom(); // new seed
      setTimeout(function(){
        tryGenerate(generatorType, map);
      }, 10)
    }

  }