instead of osgDB::Registry where it original lay. This has been done to allow
fileName strings to be encode data rather than just file names, such as one
requires when using PagedLOD along with plugins for doing dynamic tesselation.
osg::Image::setImage has also been modified to require the AllocationMode
mode to be passed to it so that it knows how to delete the data once the
image goes out of scope.
Port the image plugins across to specify the new AllocationMode, and converted
them across to using new/delete in place of malloc/free.
for settings options in osgDB::Registry, and added the paramter to all of the
reaader/writer plugins. The Options structure by default has an string attached
for packing basic options, however, it also can be subclassed to encapsulate
any users defined option data. In the later case both the client code *and*
the plugin need to be aware of subclass, the plugin will need to use
dynamic_cast<> to assertain its type.
