Remove Python < 3.6 tests from .travis.yml

.travis.yml

@@ -58,9 +58,6 @@ env:
 
     matrix:
         # Make sure that egg_info works without dependencies
-        - PYTHON_VERSION=2.7 SETUP_CMD='egg_info'
-        - PYTHON_VERSION=3.4 SETUP_CMD='egg_info'
-        - PYTHON_VERSION=3.5 SETUP_CMD='egg_info'
         - PYTHON_VERSION=3.6 SETUP_CMD='egg_info'
 
 matrix:
@@ -95,20 +92,16 @@ matrix:
         # the Numpy developers have taken care of testing Numpy with different
         # versions of Python, we can vary Python and Numpy versions at the same
         # time.
-
-        - os: linux
-          env: PYTHON_VERSION=2.7 NUMPY_VERSION=1.9
-        - os: linux
-          env: PYTHON_VERSION=3.4 NUMPY_VERSION=1.10
         - os: linux
-          env: PYTHON_VERSION=3.5 NUMPY_VERSION=1.11
+          env: PYTHON_VERSION=3.6 NUMPY_VERSION=1.13
         - os: linux
-          env: NUMPY_VERSION=1.12
+          env: PYTHON_VERSION=3.6 NUMPY_VERSION=1.14
+
 
         # Try numpy pre-release
-        - os: linux
-          env: NUMPY_VERSION=prerelease
-               EVENT_TYPE='pull_request push cron'
+#        - os: linux
+#          env: NUMPY_VERSION=prerelease
+#               EVENT_TYPE='pull_request push cron'
 
         # Do a PEP8 test with pycodestyle
         - os: linux