implement tree_view from the arrange method

[Bizcho]

A pretty print of the tree function.

TreeNode.arrange returns:

{
  #<TreeNode id: 100018, name: "Stinky", ancestry: nil> => {
    #<TreeNode id: 100019, name: "Crunchy", ancestry: "100018"> => {
      #<TreeNode id: 100020, name: "Squeeky", ancestry: "100018/100019"> => {}
    },
    #<TreeNode id: 100021, name: "Squishy", ancestry: "100018"> => {}
  }
}

TreeNode.tree_view(:name) should return:

"Stinky"
|---"Crunchy"
|----|----"Squeeky"
|---"Squishy"

[Bizcho]

I just made the pull request for this fix on the #560. Hope everithing is fine and you can add it to the repo

[kbrock]

all set

[epugh]

I was hoping to use this, but not quite understanding it.. ARe there any docs?