Added build scripts for MacOSX installer (PackageMaker)

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user: Roeland Merks <roeland.merks@cwi.nl>
branch 'default'
added src/vleafmacosx_installer.pmdoc/01virtualleaf-contents.xml
added src/vleafmacosx_installer.pmdoc/01virtualleaf.xml
added src/vleafmacosx_installer.pmdoc/02models-contents.xml
added src/vleafmacosx_installer.pmdoc/02models.xml
added src/vleafmacosx_installer.pmdoc/03leaves-contents.xml
added src/vleafmacosx_installer.pmdoc/03leaves.xml
added src/vleafmacosx_installer.pmdoc/index.xml