use pycodestyle instead of pep8 (deprecated)

.travis.yml

@@ -76,9 +76,9 @@ install:
   - pip install -r requirements.txt
 
 script:
-    # pep8 tests
-  - pep8 --ignore E501 update.py
-  - pep8 --ignore E501,E265 autocmake
+    # pycodestyle tests
+  - pycodestyle --ignore E501 update.py
+  - pycodestyle --ignore E501,E265 autocmake
     # unit tests
   - py.test -vv autocmake/*
   - py.test -vv test/test.py

doc/contributors/testing.rst

@@ -11,8 +11,8 @@ build and test recipe for other requirements.
 Your contributions and changes should preserve the test set and be PEP8 conform.
 You can run locally all tests with::
 
-  $ pep8 --ignore E501 update.py
-  $ pep8 --ignore E501,E265 autocmake
+  $ pycodestyle --ignore E501 update.py
+  $ pycodestyle --ignore E501,E265 autocmake
   $ py.test -vv autocmake/*
   $ py.test -vv test/test.py
 

requirements.txt

@@ -1,3 +1,3 @@
-pep8
+pycodestyle
 pytest
 pyyaml