PDFBOX-2057: fixed bug with lossless images with BITMASK Transparency, thanks David Keller
PDFBOX-2068: extra filter parameter for PDImageXObject(document, filteredStream) constructor

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1593569 13f79535-47bb-0310-9956-ffa450edef68