Merge pull request #64 from python/travis3

Test 2and3, 3.3, 3.4.

.travis.yml

@@ -9,5 +9,9 @@ install:
 
 script:
   - mypy stdlib/3/
+  - mypy stdlib/2and3/
+  - rm -rf 3_3; cp -R stdlib/3.3 3_3; mypy 3_3/
+  - rm -rf 3_4; cp -R stdlib/3.4 3_4; mypy 3_4/
+  - mypy --py2 stdlib/2and3/
   - rm -rf 2_7; cp -R -L stdlib/2.7 2_7; rm 2_7/__builtin__.pyi ; mypy --py2 2_7/
   # That doesn't test everything, but it's a start.