PDFBOX-2155 Fix JavaDocs warnings

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1604392 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-2155 Fix JavaDocs warnings

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1604400 13f79535-47bb-0310-9956-ffa450edef68