[UIMA-3247] [UIMA-3300] only run sign for source-release if the source-release.zip exists. (It's not built except at the executionRoot).  Upgrade Antrun plugin version, including its ant-apache-regex dependency. Upgrade enforcer plugin to more recent version. add RAT exclusion for .ppt (powerpoint) files used to hold some sources for pictures in documentation.
[UIMA-3247] [UIMA-3300] only run sign for source-release if the source-release.zip exists. (It's not built except at the executionRoot).  Upgrade Antrun plugin version, including its ant-apache-regex dependency. Upgrade enforcer plugin to more recent version. add RAT exclusion for .ppt (powerpoint) files used to hold some sources for pictures in documentation.

git-svn-id: 71fdd81d427d1664ceef220cd41fb697a2614719@1525954 13f79535-47bb-0310-9956-ffa450edef68

apache/uima-build,apache/uima-build,apache/uima-build