PDFBOX-1969: more refactoring; removed useless line; added graphics.dispose() call; prepare test for ARGB image

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1577878 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-1975: expand JPEGUtil for missing nodes in metadata; some refactoring

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1577931 13f79535-47bb-0310-9956-ffa450edef68
PDFBOX-1983: Unable to add TIF images, CCITTFactory not working

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1577959 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'apache/trunk' into trunk