[UIMA-4153] slight performance improvements, maybe...

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1645693 13f79535-47bb-0310-9956-ffa450edef68
[UIMA-4135] update readme / release notes to current impl state


git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1645723 13f79535-47bb-0310-9956-ffa450edef68
[UIMA-4146] [UIMA-4135] fix create of snapshot index - was missing setting the index size. Also improve performance of check for invalid feature setting.

git-svn-id: https://svn.apache.org/repos/asf/uima/uimaj/trunk@1645735 13f79535-47bb-0310-9956-ffa450edef68