FOP-2292: First bits of a whitespace management extension
Patch by Seifeddine Dridi, applied with some modifications (mainly, Java compliance and Checkstyle)


git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/Temp_WhitespaceManagement@1518691 13f79535-47bb-0310-9956-ffa450edef68