Add python 3.5 support for tox; run all tests before a release

tasks.py

@@ -1,8 +1,8 @@
-# -*- coding: utf-8 -*-
+# -*- coding: utf-8; -*-
 ################################################################################
 #
 #  Rattail -- Retail Software Framework
-#  Copyright © 2010-2017 Lance Edgar
+#  Copyright © 2010-2018 Lance Edgar
 #
 #  This file is part of Rattail.
 #
@@ -21,19 +21,21 @@
 #
 ################################################################################
 """
-Fabric script for Tailbone
+Tasks for Tailbone
 """
 
 from __future__ import unicode_literals, absolute_import
 
 import shutil
-from fabric.api import task, local
+
+from invoke import task
 
 
 @task
-def release():
+def release(ctx):
     """
     Release a new version of 'Tailbone'.
     """
+    ctx.run('tox')
     shutil.rmtree('Tailbone.egg-info')
-    local('python setup.py sdist --formats=gztar upload')
+    ctx.run('python setup.py sdist --formats=gztar upload')

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py26, py27
+envlist = py27, py35
 
 [testenv]
 deps =