Removed nightly build.

There are issues popping up with NoseTests causing the nightly build to fail.

Author: dalymople

.travis.yml

@@ -7,7 +7,6 @@ python:
   - "3.8"
   - "3.9"
   - "3.9-dev"  # 3.9 development branch
-  - "nightly"  # nightly build
 # command to install dependencies
 install:
   - pip install -r requirements.txt