[UIMA-4003] improve/simplify/make work for small sizes, the switching logic for PositiveIntSet. 

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1623869 13f79535-47bb-0310-9956-ffa450edef68
no Jira, fix misc javadoc issues

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1623870 13f79535-47bb-0310-9956-ffa450edef68