VisdomOutput for the logger

[ryanjulian]

This is worth a try

https://github.com/facebookresearch/visdom

[zhanpenghe]

I was also reading about this for the pytorch tree implementation. I think it is a good visualization tool for it.

[ryanjulian]

I think it should be supported for all trees.

[ryanjulian]

@pelillian another potential logger feature