Split CI into stages

.travis.yml

@@ -18,20 +18,23 @@ addons:
 language: python
 install: tests/install.sh
 script: tests/test.sh
-matrix:
+jobs:
     include:
-        - python: "2.6"
-        - python: "2.7"
+        - stage: Old Python and PyPy
+          python: "2.6"
         - python: "3.2"
-        - python: "3.3"
-        - python: "3.4"
-        - python: "3.5"
-        - python: "3.6"
         - python: "pypy"
         - python: "pypy3"
+        - stage: Latest Python
+          python: "2.7"
         - python: "2.7"
           env: >-
             USE_UCS2_PYTHON=1
             UCS2_PYTHON_VARIANT="2.7"
+        - python: "3.6"
+        - stage: Intermediate versions
+          python: "3.3"
+        - python: "3.4"
+        - python: "3.5"
 
 # vim: et