[UIMA-4135] add support for removing and adding back multiples of the same value, in support of avoiding index corruption, where allow_duplicate_add_to_indices is true.

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1644149 13f79535-47bb-0310-9956-ffa450edef68
[UIMA-4105] - clarify moveTo where multiple candidates match, moves to "leftmost" one.

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1644153 13f79535-47bb-0310-9956-ffa450edef68
no Jira - comment change

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1644154 13f79535-47bb-0310-9956-ffa450edef68
[UIMA-4146] add snapshot API, clarify comments

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1644163 13f79535-47bb-0310-9956-ffa450edef68
no Jira - make many fields final

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1644164 13f79535-47bb-0310-9956-ffa450edef68