Drop support for Python < 3.5

.travis.yml

@@ -1,10 +1,9 @@
 language: python
+dist: xenial
 python:
-- 2.7
-- 3.4
 - 3.5
 - 3.6
-- 3.7-dev
+- 3.7
 before_install:
 - pip install codecov
 - pip install -r requires/testing.txt
@@ -22,6 +21,6 @@ deploy:
   password:
     secure: ARvFw5CHqQZqPOkJXxQSe7EAEbX1yt7FiBTtzz8Gd6XndbY10HVCSWhGYeldm9LevvQc9p77pBEvsl+bXGQbJ3NW/r/U5PADaFdmi4bxmXN8yc+dFKzn72MpZfL+kCV2T/HutuOY6dQa4okTkKVV+sqwPLKPhL69zH/PxQg8qe4=
   on:
-    python: 3.4
+    python: 3.7
     tags: true
     all_branches: true

requires/installation.txt

@@ -1,2 +1 @@
-tornado>=3.1,<5; python_version < '3.4'
-tornado>=3.1,<6; python_version >= '3.4'
+tornado>=3.1,<6

setup.py

@@ -48,11 +48,10 @@ setuptools.setup(
         'License :: OSI Approved :: BSD License',
         'Natural Language :: English',
         'Operating System :: OS Independent',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Internet :: WWW/HTTP',
@@ -60,5 +59,6 @@ setuptools.setup(
         'Topic :: Software Development :: Libraries :: Python Modules'],
     test_suite='nose.collector',
     tests_require=tests_require,
+    python_requires='>=3.5',
     zip_safe=True,
 )