First pass at a working tree model where the leaf nodes don't need to derive from a common base object type (only internal nodes of the tree derive from ITreeNode). To achieve this, the code stores a pointer to the item's ITreeNode parent in the internalPointer of model indexes.
Added some comments and minor cleanup to test code.
Merge branch 'master' of https://github.com/InvictusInnovations/BitShares
Get windows version compiling again. Still need to re-enable my bitsharesgui code in bitsharesgui.pro and compile that.