Add flake8 to Travis-CI to prevent these from coming back

Added new travis make target to skip flake8 on pypy but run it on all others

.travis.yml

@@ -13,7 +13,7 @@ install:
   - if [[ $TRAVIS_PYTHON_VERSION == 'pypy' ]]; then pip install astor --use-mirrors; fi
   - python setup.py -q install
 # # command to run tests
-script: nosetests
+script: make travis
 notifications:
   email:
     - paultag@gmail.com

Makefile

@@ -52,5 +52,12 @@ diff:
 
 r: d tox diff
 
+travis:
+	nosetests -s
+ifeq (PyPy,$(findstring PyPy,$(shell python -V 2>&1 | tail -1)))
+	@echo "skipping flake8 on pypy"
+else
+	flake8 hy bin tests
+endif
 
 .PHONY: docs

hy/util.py

@@ -25,4 +25,4 @@ import sys
 if sys.version_info[0] >= 3:
     str_type = str
 else:
-    str_type = unicode
+    str_type = unicode  # NOQA

requirements.txt

@@ -1,2 +1,3 @@
 # Check site / dev for more deps!
+flake8
 -e git+https://github.com/hylang/rply.git#egg=rply