remove deprecated pytest-runner (fully rely on tox instead)

t is recommended that you:

    Remove 'pytest-runner' from your setup_requires, preferably removing the setup_requires option.
    Remove 'pytest' and any other testing requirements from tests_require, preferably removing the tests_requires option.
    Select a tool to bootstrap and then run tests such as tox.

Author: Bomme

.travis.yml

@@ -14,6 +14,7 @@ addons:
 
 install:
     - python setup.py install
+    - pip install tox
 
 script:
-    - pytest
+    - tox

setup.cfg

@@ -36,11 +36,6 @@ def _read(fn):
 
       packages=['audioread'],
 
-      tests_require=[
-          'pytest-runner',
-          'pytest'
-      ],
-
       classifiers=[
           'Topic :: Multimedia :: Sound/Audio :: Conversion',
           'Intended Audience :: Developers',