PDFBOX-2169: improve error for missing standard font (partial push)

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1606970 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-2169: added TTF fallback font

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1606972 13f79535-47bb-0310-9956-ffa450edef68