Report coverage on Travis

In the long run I want to add --fail-under=100 so Travis enforces 100%
test coverage (because Coveralls doesn't do that!).  This is complicated
because of Python 2 vs Python 3 code paths mean each Travis job gets
like 98% coverage, and I get 100% only when I combine them all.

I hear newer versions of coverage will (or maybe already do) allow
different nocover pragmas for different Python versions, so it'll be
possible with some extra work.

.travis.yml

@@ -15,5 +15,6 @@ script:
     - coverage run --source=irclog2html -m zope.testrunner --test-path=src
 after_script:
     - coveralls
+    - coverage report -m
 notifications:
     email: false