Switch to flake8-docstrings with pydocstyle

We used to use flake8-pep257 because docstrings claims no codes are ignorable
(which is wrong). However, that doesn't work with pydocstyle, so we had a
separate pydocstyle environment (and flake8-pep257 to check tests with relaxed
rules).

Now we only use flake8-docstrings + pydocstyle (which it switches to if it's
available, even though it still depends on pep257), and drop the pydocstyle tox
env.

As soon as flake8-docstrings is updated to drop the (unneeded) pep257
dependency, we can drop it as well.

.travis.yml

@@ -16,7 +16,6 @@ env:
     - TESTENV=unittests-nodisp
     - TESTENV=misc
     - TESTENV=vulture
-    - TESTENV=pydocstyle
     - TESTENV=flake8
     - TESTENV=pyroma
     - TESTENV=check-manifest
@@ -52,8 +51,6 @@ matrix:
       env: TESTENV=misc
     - os: osx
       env: TESTENV=vulture
-    - os: osx
-      env: TESTENV=pydocstyle
     - os: osx
       env: TESTENV=flake8
     - os: osx

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py34,py35-cov,misc,vulture,pydocstyle,flake8,pylint,pyroma,check-manifest
+envlist = py34,py35-cov,misc,vulture,flake8,pylint,pyroma,check-manifest
 
 [testenv]
 # https://bitbucket.org/hpk42/tox/issue/246/ - only needed for Windows though
@@ -149,13 +149,6 @@ commands =
     {envpython} -m pylint scripts qutebrowser --output-format=colorized --reports=no
     {envpython} scripts/dev/run_pylint_on_tests.py --output-format=colorized --reports=no
 
-[testenv:pydocstyle]
-basepython = python3
-skip_install = true
-passenv = PYTHON LANG
-deps = pydocstyle==1.0.0
-commands = {envpython} -m pydocstyle scripts tests qutebrowser
-
 [testenv:flake8]
 basepython = python3
 passenv =
@@ -174,8 +167,9 @@ deps =
     flake8-deprecated==0.2
     flake8-mock==0.2
     flake8-pep3101==0.2
-    flake8-pep257==1.0.5
-    pep257==0.7.0
+    flake8-docstrings==0.2.5
+    pep257==0.7.0  # still needed by flake8-docstrings but ignored
+    pydocstyle==1.0.0
 commands =
     {envpython} -m flake8