setup.py doesn't specify dependencies correctly #70

Thanks for this package, it's exactly what I've been looking for!

On a fresh Ubuntu install, pip3 install dabest does not install any of the dependencies:

$ sudo apt install python3 python3-pip
# ...
done.
$ pip3 install dabest
Collecting dabest
  Downloading https://files.pythonhosted.org/packages/4b/05/baaf3990f30347f9780977b6b102036b6cbe22a8027e13f331c13e585873/dabest-0.2.5-py2.py3-none-any.whl (61kB)
    100% |################################| 71kB 1.5MB/s 
Installing collected packages: dabest
Successfully installed dabest-0.2.5

If you (unconditionally) specify the dependencies in setup.py then pip will install them automatically. It'd also stop everyone re-reporting the same issues because they have incompatible versions of dependencies (#52, #60, #67).

I'll send you a PR.