CreateSingleDir


git-svn-id: https://geuz.org/svn/gmsh/trunk@17808 59c8cabf-10d6-4a28-b43f-3936b85956c4
treat PDF and bitmap bagrounds the same + allow using 3D (in model coords) background



git-svn-id: https://geuz.org/svn/gmsh/trunk@17809 59c8cabf-10d6-4a28-b43f-3936b85956c4