Issue with pip install -e git+git_repo_address

[heungseok]

Hi,
I'm trying to install visdom via source code to use new features such as audio, video, and others.
Also, I want to install the visdom via setup.py or requirements.txt by using the command like "git+git_repo_address"
However, the install didn't work even the message said success.

Got fails from setup.py and requirements.txt, I also tried to install visdom for local, but the results are same as following.

~user$ pip install -e git+https://github.com/facebookresearch/visdom.git@master#egg=visdom
Obtaining visdom from git+https://github.com/facebookresearch/visdom.git@master#egg=visdom
  Updating ./src/visdom clone (to master)
Requirement already satisfied: numpy>=1.8 in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: scipy in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: pillow in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: requests in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: tornado in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: pyzmq in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: six in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: torchfile in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: websocket-client in /Users/user/anaconda3/lib/python3.6/site-packages (from visdom)
Requirement already satisfied: olefile in /Users/user/anaconda3/lib/python3.6/site-packages (from pillow->visdom)
Requirement already satisfied: chardet<3.1.0,>=3.0.2 in /Users/user/anaconda3/lib/python3.6/site-packages (from requests->visdom)
Requirement already satisfied: idna<2.7,>=2.5 in /Users/user/anaconda3/lib/python3.6/site-packages (from requests->visdom)
Requirement already satisfied: urllib3<1.23,>=1.21.1 in /Users/user/anaconda3/lib/python3.6/site-packages (from requests->visdom)
Requirement already satisfied: certifi>=2017.4.17 in /Users/user/anaconda3/lib/python3.6/site-packages (from requests->visdom)
Installing collected packages: visdom
  Found existing installation: visdom 0.1.7.2
    Uninstalling visdom-0.1.7.2:
      Successfully uninstalled visdom-0.1.7.2
  Running setup.py develop for visdom
Successfully installed visdom
~user$ python -m visdom.server
/Users/user/anaconda3/bin/python: No module named visdom.server

I think this issue is closely related with the closed issue #16, so the problem seems in install "pip install -e . ", and I think the issue is not fixed yet.

[JackUrb]

I've finally found the root cause of this issue (been able to reproduce it recently) though I don't think I'll understand why pip install -e . ever would work before on certain systems. Seems that setuptools ignores the package_dir param when the sourced directory is the package directory rather than contains the package directory. I've put together a fix in #281