Reuse WrapperTestFixture in an integration test.
Some int test simplifications.
Don't use --stacktrace in int tests (the fixtures take care of this).
Added some context to the error message when we can't load or transform a class from the groovy compile classpath.
Revert "updated Sonar Runner to 2.2"

This reverts commit 21da83a88b979895caa615f4dbfb0968ff09525b.
Revert "only run integ test for sonar-runner plugin on jdk6 and higher (latest sonar runner no longer supports jdk5)"

This reverts commit e6dd351a77d601505282ff2ab7a6956bcca4013f.