chore(travis): +py36, +pypy3, no-sudo, with tox-travis plugin

from https://github.com/tox-dev/tox-travis

.travis.yml

@@ -1,19 +1,20 @@
-sudo: travis
+sudo: false
 language: python
-python: 3.5
-env:
-  - TOX_ENV=py27
-  - TOX_ENV=py33
-  - TOX_ENV=py34
-  - TOX_ENV=py35
-  - TOX_ENV=pypy
+python:
+  - 2.7
+  - 3.3
+  - 3.4
+  - 3.5
+  - 3.6
+  - pypy
+  - pypy3
 
 install:
-  - pip install -U setuptools pip sphinx tox
+  - pip install -U setuptools pip sphinx tox tox-travis
 
 script:
   - ./bin/test_standalone.sh
-  - tox -e $TOX_ENV
+  - tox
   - ./bin/check_readme.sh
 
 branches:

bin/gen-standalone.sh

@@ -22,7 +22,7 @@ wheel="./dist/pypiserver-*.whl"
 #   prepend it with a python-flashbang + some header-comments >= 10-lines
 #   so that ``head pypiserver*.py``behaves politely.
 #
-sudo update-ca-certificates
+sudo update-ca-certificates || echo "Failed updating certs (run on travis container?)"
 unzip -jo $wheel pypiserver/__main__.py -d ./dist
 zip -d $wheel pypiserver/__main__.py
 zip -mj $wheel ./dist/__main__.py