remove python 3.3 from CI (#3729)

* remove python 3.3 from CI

* remove 3.3 everywhere, not just from CI
diff --git a/Jenkinsfile b/Jenkinsfile
index 5440093..50f53a2 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -5,11 +5,11 @@
 def configs = [
     [
         label: 'windows',
-        toxenvs: ['py26', 'py27', 'py33', 'py34', 'py35', 'py36'],
+        toxenvs: ['py26', 'py27', 'py34', 'py35', 'py36'],
     ],
     [
         label: 'windows64',
-        toxenvs: ['py26', 'py27', 'py33', 'py34', 'py35', 'py36'],
+        toxenvs: ['py26', 'py27', 'py34', 'py35', 'py36'],
     ],
     [
         label: 'freebsd11',
@@ -199,7 +199,6 @@
                         def pythonPath = [
                             py26: "C:\\Python26\\python.exe",
                             py27: "C:\\Python27\\python.exe",
-                            py33: "C:\\Python33\\python.exe",
                             py34: "C:\\Python34\\python.exe",
                             py35: "C:\\Python35\\python.exe",
                             py36: "C:\\Python36\\python.exe"