Go back to using conda.

.travis.yml

@@ -2,9 +2,19 @@ language: python
 python:
 - '3.6'
 before_install:
-- sudo apt-get -qq update
-- sudo apt-get install -y python3-numba
+- if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then wget https://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh
+  -O miniconda.sh; else wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
+  -O miniconda.sh; fi
+- bash miniconda.sh -b -p $HOME/miniconda
+- export PATH="$HOME/miniconda/bin:$PATH"
+- hash -r
+- conda config --set always_yes yes --set changeps1 no
+- conda update -q conda
+- conda info -a
 install:
+- conda create -q -n testenv --yes pip python=$TRAVIS_PYTHON_VERSION
+- source activate testenv
+- conda install --yes numpy scipy numba
 - pip install -r requirements_dev.txt
 - python setup.py install
 script: