* refactor copying and freeing of node->storage by handlerizing them.
- freestoragefunc
- copystoragefunc
- node_util.c/h have generic handlers for these.
This will allow python or plugin defined nodes to work as well.
(And fixes compile issues with MSVC in yesterdays commit for nodes)
Code provided by Nathan L.
Fixes in his code:
- free_nodesystem() was called too late (after guarded alloc was closed)
- free_nodesystem() was freeing nodes that were not malloced even
- free_nodesystem was using free, not freeN :)
- the typedefs needed to be malloced yes, to allow duplicate nodes like
group but also for dynamic nodes.
