Revise Travis-CI configuration to enable scipy

The default Travis-CI system image does not include scipy, so including it in requirements.txt will yield a build error. The current workaround employs miniconda to install both numpy and scipy, as referenced in travis-ci/travis-ci#2650. An alternate approach is proposed in travis-ci/travis-ci#2638.

.travis.yml

@@ -1,11 +1,29 @@
+# Based on https://gist.github.com/dan-blanchard/7045057 and modifications in
+# https://github.com/Jorge-C/ordination/blob/master/.travis.yml
+# See also: https://github.com/travis-ci/travis-ci/issues/2650
+
 language: python
 python:
-  - "3.2"
-  - "3.3"
   - "3.4"
   - "3.5"
-# command to install dependencies
-install: "pip3 install -r requirements.txt"
-# command to run tests
+
+# Download and set up anaconda
+before_install:
+  - wget http://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh -O miniconda.sh
+  - chmod +x miniconda.sh
+  - ./miniconda.sh -b
+  - export PATH=/home/travis/anaconda/bin:$PATH
+  # Update conda itself
+  - conda update --yes conda
+  # The next couple lines fix a crash with multiprocessing on Travis and are not specific to using Miniconda
+  - sudo rm -rf /dev/shm
+  - sudo ln -s /run/shm /dev/shm
+
+# Install packages
+install: 
+  - conda install --yes python=$TRAVIS_PYTHON_VERSION numpy scipy
+  - python setup.py install
+
+# Run test(s)
 script: 
   - python3 -m unittest discover -p '*_test.py'