UIMA-3894 revert to 2.6.0-SNAPSHOT

git-svn-id: https://svn.apache.org/repos/asf/uima/uima-as/trunk@1603503 13f79535-47bb-0310-9956-ffa450edef68
UIMA-3901 missing license and notices

git-svn-id: https://svn.apache.org/repos/asf/uima/uima-as/trunk@1603511 13f79535-47bb-0310-9956-ffa450edef68