fix various cython related errors

tested with python 3.7.3 and python 2.7.10

.travis.yml

@@ -1,12 +1,14 @@
 language: python
 python:
+  - "3.6"
+  - "3.5"
   - "3.4"
   - "3.3"
-  - "3.2"
   - "2.7"
   - "2.6"
 
 install:
+  - pip install -q cython
   - python setup.py install
 
 # command to run tests, e.g. python setup.py test

setup.py

@@ -1,6 +1,7 @@
 #! /usr/bin/env python
 import glob
 from setuptools import setup, Extension
+from Cython.Build import cythonize
 
 setup(
     name="DAWG",
@@ -11,14 +12,14 @@
     author_email='kmike84@gmail.com',
     url='https://github.com/pytries/DAWG/',
 
-    ext_modules = [
+    ext_modules = cythonize(
         Extension(
             "dawg",
-            sources = glob.glob('src/*.cpp') + glob.glob('lib/b64/*.c'),
+            glob.glob('src/dawg.pyx') + glob.glob('lib/b64/*.c'),
             include_dirs=['lib'],
             language = "c++",
         )
-    ],
+    ),
 
     classifiers=[
         'Development Status :: 4 - Beta',