installation issue with python3.6 in conda

`pip install clodius` installation under conda python3.6 was giving me this (already after `conda install pyBigWig`):
```
Collecting clodius==0.7.4
Using cached clodius-0.7.4.tar.gz
Requirement already satisfied: cython in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: numpy in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Collecting negspy (from clodius==0.7.4)
Using cached negspy-0.2.20.tar.gz
Requirement already satisfied: pysam in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: requests in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: h5py in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: pandas in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Collecting slugid (from clodius==0.7.4)
Using cached slugid-1.0.7.tar.gz
Requirement already satisfied: sortedcontainers in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: nose in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Requirement already satisfied: pyBigWig in /home/venevs/miniconda3/lib/python3.6/site-packages (from clodius==0.7.4)
Exception:
Traceback (most recent call last):
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/basecommand.py", line 215, in main
status = self.run(options, args)
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/commands/install.py", line 335, in run
wb.build(autobuilding=True)
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/wheel.py", line 749, in build
self.requirement_set.prepare_files(self.finder)
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/req/req_set.py", line 380, in prepare_files
ignore_dependencies=self.ignore_dependencies))
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/req/req_set.py", line 666, in _prepare_file
check_dist_requires_python(dist)
File "/home/venevs/miniconda3/lib/python3.6/site-packages/pip/utils/packaging.py", line 48, in check_dist_requires_python
feed_parser.feed(metadata)
File "/home/venevs/miniconda3/lib/python3.6/email/feedparser.py", line 175, in feed
self._input.push(data)
File "/home/venevs/miniconda3/lib/python3.6/email/feedparser.py", line 103, in push
self._partial.write(data)
TypeError: string argument expected, got 'NoneType'
```

everything worked after manually installing `negspy` at first: `pip install negspy` and `slugid` and forcing `clodius` to be installed without dependencies:
```pip install 'clodius==0.7.4' --force-reinstall --no-deps```