drop code coverage for now

Something is broken on travis-ci.org regarding the max execution time
limit and code coverage generation. I have no clue how to solve this, so
I remove this again for test completion's sake.

Please chime in with ideas at

* https://github.com/travis-ci/travis-ci/issues/1837
* http://stackoverflow.com/q/20972248/172068

.travis.yml

@@ -9,8 +9,4 @@ notifications:
         - "chat.freenode.net#dokuwiki"
     on_success: change
     on_failure: change
-script: cd _test && phpunit --stderr --coverage-clover=coverage.clover
-
-after_script:
-  - wget https://scrutinizer-ci.com/ocular.phar
-  - php ocular.phar code-coverage:upload --format=php-clover coverage.clover
+script: cd _test && phpunit --stderr