More pleasure tree branch format

[voronind]

Output looks like this

pipdeptree==0.11.0
  - pip==9.0.1 [required: >=6.0.0]
pytest==3.4.2
  - attrs==17.4.0 [required: >=17.2.0]
  - pluggy==0.6.0 [required: <0.7,>=0.5]
  - py==1.5.2 [required: >=1.5.0]
  - setuptools==28.8.0 [required: Any]
  - six==1.11.0 [required: >=1.10.0]
tox==2.9.1
  - pluggy==0.6.0 [required: <1.0,>=0.3.0]
  - py==1.5.2 [required: >=1.4.17]
  - six==1.11.0 [required: Any]
  - virtualenv==15.1.0 [required: >=1.11.2]

[naiquevin]

IMO the current format is more explicit. Not merging this unless there's a convincing explanation.

[voronind]

It's just regular notation. It's closer to --reverse output. There is no strong reasons.

[gaborbernat]

Closing as this seems to have stalled.