[K3d-development] Valgrind error in SigC

[Ed M. <emi...@di...>]

A ValGrind free memory read error is attached.  This is from a k3d
snapshot from a week or so ago, apologies if its old news.  The workflow
is to create a new document and on the context menu:

	Add Parent...->Cone
	Exit with Discard Changes.  

Not sure if this is a valid workflow but it was the closest thing I
could at first blush to create an object though "Add Parent" is kind of
a odd name for "Create" so maybe its a bogus work flow.

It appears to be a free memory read in close_document() from 
k3d::object::~object() on SigC stuff freed in:

	object_collection_implementation::on_close_document()

I'm using SigC 1.2 though I know its been banned.

-- Ed