Check proper closure sequence of Statements/Connections/Env SQLDisconnect now closes automatically all attached statements.
So now struct _hdbc contains the real allocated data. SQLAllocConnect doesn't hack it anymore with its own stucture.
mdbprivate is.... private. mdbodbc.h has no reason to be public: People who want to use the plugin should use the public odbc.h headers. And having this private will permit hdbc cleanup.
