PDFBOX-2386: Move operators and PDFStreamEngine(s) to new package

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1627856 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-2385: Clean Up

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1627857 13f79535-47bb-0310-9956-ffa450edef68