Support Python 3.7 (#204)

Add tests for Python 3.7 while keeping Python 3.6 as the default version.

Author: seisman

.travis.yml

@@ -41,6 +41,10 @@ matrix:
               - BUILD_DOCS=true
               - DEPLOY_DOCS=true
               - DEPLOY_PYPI=true
+        - os: linux
+          env:
+              - PYTHON=3.7
+              - BUILD_DOCS=true
         - os: osx
           env:
               - PYTHON=3.5
@@ -50,6 +54,10 @@ matrix:
               - PYTHON=3.6
               - COVERAGE=true
               - BUILD_DOCS=true
+        - os: osx
+          env:
+              - PYTHON=3.7
+              - BUILD_DOCS=true
 
 before_install:
     # Get the Fatiando CI scripts

setup.py

@@ -37,6 +37,7 @@
     "Topic :: Software Development :: Libraries",
     "Programming Language :: Python :: 3.5",
     "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.7",
     "License :: OSI Approved :: {}".format(LICENSE),
 ]
 PLATFORMS = "Any"