Modernize

1. Update the travis script to follow their multi-OS example.
2. Set the path to Python in the osx bulid wheels script.
3. Add newlines to a couple requirements.
4. For osx, removed all versions of python except 3.7 and 3.8.

.travis.yml

@@ -1,17 +1,15 @@
-sudo: required
-
-matrix:
-  include:
-    - dist: trusty
-      language: python
-      services:
-        - docker
-      script:
-        - ./make/manylinux1/build_wheels.sh
-    - os: osx
-      osx_image: xcode8.3
-      script:
-        - ./make/osx/build_wheels.sh
+language: generic
 
+jobs:
+    include:
+        - os: linux
+          services:
+              - docker
+          script:
+              - ./make/manylinux1/build_wheels.sh
+        - os: osx
+          osx_image: xcode9.4
+          script:
+              - ./make/osx/build_wheels.sh
 install:
   - if [ "${TRAVIS_OS_NAME:-}" == "osx" ]; then ./make/osx/install_python.sh; fi

make/osx/build_wheels.sh

@@ -1,10 +1,11 @@
 set -e
 set +x
 
-for VER in 2.7 3.4 3.5 3.6 3.7; do
+for VER in 3.7 3.8; do
     PIP="pip${VER}"
     PYTHON="python${VER}"
     VENV="venv_${VER}"
+    PATH="/Library/Frameworks/Python.framework/Versions/${VER}/bin:$PATH"
 
     # update pip for newer TLS support
     curl https://bootstrap.pypa.io/get-pip.py | ${PYTHON}

make/osx/install_python.sh

@@ -3,10 +3,8 @@ set -euo pipefail
 set -x
 
 URLS=(
-    'https://www.python.org/ftp/python/2.7.14/python-2.7.14-macosx10.6.pkg'
-    'https://www.python.org/ftp/python/3.4.4/python-3.4.4-macosx10.6.pkg'
-    'https://www.python.org/ftp/python/3.5.4/python-3.5.4-macosx10.6.pkg'
-    'https://www.python.org/ftp/python/3.6.4/python-3.6.4-macosx10.6.pkg'
+    'https://www.python.org/ftp/python/3.7.9/python-3.7.9-macosx10.9.pkg'
+    'https://www.python.org/ftp/python/3.8.6/python-3.8.6-macosx10.9.pkg'
 )
 
 for url in "${URLS[@]}"; do

requirements/setup.txt

@@ -1 +1 @@
--r prod.txt
+-r prod.txt

requirements/test.txt

@@ -1,3 +1,3 @@
 -r prod.txt
 tox
-pytest
+pytest