hint at Permissions manifest attribute and signing requirements for applets in upcoming 7u51 - PR 55542 - Submitted by Erik Costlow

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1521727 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/ant into JUnitNonTestsSkipped