It's really just a cut-paste job from the existing LINE support.
The current dxf plugin architecture isn't very efficient, especially if you
are loading large point clouds (LIDAR)
eg. it makes multiple lookups of the layer name for each vertex.
I don't know if I can improve this for the general case or if I have to add a
special large point cloud dxf reader."
dxfSection classes, so their members data are correctly deleted.
- changed some methods signatures to pass arguments by reference instead of
by value. The performance and memory usage are enhanced (the reader was
clogging the heap when reading some large DXF files)
The updated files have been compiled and tested with a variety of DXF files
on XP with VS2003, but the changes should not disturb any other compiler."
