Fix Travis test-runner

- $result was getting calculated incorrectly
- use --stderr switch for phpunit

.travis/run-tests.sh

@@ -7,8 +7,8 @@ result=0
 for tested in "${testedcomponents[@]}"
     do
         echo "$tested:"
-        phpunit -c $testdir/phpunit.xml $testdir/$tested
-        let "result = $result || $?"
+        phpunit -c $testdir/phpunit.xml --stderr $testdir/$tested
+        result=$(($result || $?))
 done
 
-exit $result
+exit $result