MAINT: add benchmarks to Travis-CI pyflakes+pep8 checks

.travis.yml

@@ -12,8 +12,8 @@ matrix:
         - pip install pep8==1.5.1
         - pip install pyflakes
       script:
-        - PYFLAKES_NODOCTEST=1 pyflakes scipy | grep -E -v 'unable to detect undefined names|assigned to but never used|imported but unused|redefinition of unused' > test.out; cat test.out; test \! -s test.out
-        - pep8 scipy
+        - PYFLAKES_NODOCTEST=1 pyflakes scipy benchmarks/benchmarks | grep -E -v 'unable to detect undefined names|assigned to but never used|imported but unused|redefinition of unused' > test.out; cat test.out; test \! -s test.out
+        - pep8 scipy benchmarks/benchmarks
     - python: 3.4
       env:
         - TESTMODE=fast