add incubator logo

git-svn-id: https://svn.apache.org/repos/asf/incubator/sirona/trunk@1540950 13f79535-47bb-0310-9956-ffa450edef68
add footer with trademark

git-svn-id: https://svn.apache.org/repos/asf/incubator/sirona/trunk@1540951 13f79535-47bb-0310-9956-ffa450edef68
add ASF Links

git-svn-id: https://svn.apache.org/repos/asf/incubator/sirona/trunk@1540952 13f79535-47bb-0310-9956-ffa450edef68