Verify that the site goal is working.

Currently you could not create the site with Java 8. Unfortunately I didn't know about this. In order to avoid such an accident we will build the site on the CI server, too.
Disable parts of doclint for the site's javadoc.

This is a follow-up to e0367cd. That commit is missing to apply the doclint rules to site generation. Hence the site goal fails because of doclint issues. Now doclint is disabled for all groups but accessibility and reference for the site generation, too.
adjust JavaDoc to reflect that temporary folders are not guaranteed to be deleted
Merge pull request #1021 from UrsMetz/adjust-temporary-folder-javadoc

JavaDoc of TemperaryFolder: folder not guaranteed to be deleted
Fix Incompatibility with JDK5 source level

@Override is not allowed when implementing an interface method
Merge pull request #1022 from stefanbirkner/travis-site

Verify that the site goal is working.
Merge pull request #1025 from marcphilipp/fix-jdk5-incompatibility

Fix Incompatibility with JDK5 source level
Add missing pull requests from 4.12 release notes.
Merge pull request #1024 from kcooney/update-release-notes

Add missing pull requests from 4.12 release notes