Add tree visualization

[sv-gray]

Could we get some way of visualizing the current tree? For example:

.selector('wander around')
  .do('do nothing if unit is already moving', CheckMotion.checkIfMoving())
  .sequence('perform wander sequence')
    .do('wait for some time', Wait.wait())
    .do('locate a fitting tile', Tile.locateFitting())
    .do('go to tile', Tile.goToPoint())
    .do('reset wait cycle', Wait.reset())
  .end()
.end()
.build();

const tree = wanderBehavior.tick();
const treeLooksLike = {
  'wander around': {
    name: 'wander around',
    result: 'RUNNING',
    children: {
      'do nothing if already moving': {
        name: 'do nothing if already moving',
        result: 'FAILURE'
      },
      'perform wander sequence': {
        name: 'perform wander sequence',
        result: 'RUNNING',
        children: {
          'wait for some time': {
             name: 'wait for some time',
             result: 'SUCCESS'
          },
          'locate fitting tile': {
             ...,
             result: 'SUCCESS'
          },
          'go to tile': {
            ...,
            result: 'RUNNING'
          },
          'reset wait cycle': {
            ...,
            result: 'SUCCESS' //or maybe 'UNREACHED'? since the tree hasn't reached this point yet, as the previous action is still RUNNING
          }
        }
      }
    }
  }
}

Then you can feed this into your console.log or your tree visualizer package.

I'll see if I can put together a PR if you're interested in having this in the main branch.