Remove pipenv commands, resolve pandas dependency issue, remove TD test

This commit fixes issue in testing

1. Removes the pipenv installation steps prior to testing
2. Fixes the pandas==0.23 dependency issue
3. Remove the TD testing

For point 3, this is a temporary measure whilst lalsuite#153 (closed) is investigated.

.gitlab-ci.yml

@@ -42,9 +42,6 @@ basic-3.7:
 python-2.7:
   stage: test
   image: bilbydev/bilby-test-suite-python27
-  before_script:
-    # Install the dependencies specified in the Pipfile
-    - pipenv install --two --python=/opt/conda/bin/python2 --system --deploy
   script:
     - python setup.py install
     # Run tests without finding coverage
@@ -54,9 +51,6 @@ python-2.7:
 python-3.7:
   stage: test
   image: bilbydev/bilby-test-suite-python37
-  before_script:
-    # Install the dependencies specified in the Pipfile
-    - pipenv install --three --python=/opt/conda/bin/python --system --deploy
   script:
     - python setup.py install