update build system for windows

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2492 a5045d30-4826-4484-9c7f-6e55a06ddc77
expose a few more descriptors

git-svn-id: svn://svn.code.sf.net/p/rdkit/code/trunk@2495 a5045d30-4826-4484-9c7f-6e55a06ddc77