Travis-CI: add Python 3.2, PyPy, and PyPY3 as acceptable failures

Allows monitoring to see how close we are to supporting these on these
platforms.

.travis.yml

@@ -2,9 +2,17 @@ sudo: false  # run on new infrastructure
 language: python
 python:
   - "2.7"
+  - "3.2"
   - "3.3"
   - "3.4"
   - "3.5"
+  - "pypy"
+  - "pypy3"
+matrix:
+  allow_failures:
+    - python: "3.2"
+    - python: "pypy"
+    - python: "pypy3"
 install:
   - "pip install ."
   - "pip install icalendar"