Added some additional data to exception raised in PropertyLoader,_get_direction when cannot determine the direction to specify exactly which relation failed.
Added some additional data to exception raised in PropertyLoader,_get_direction when cannot determine the direction to specify exactly which relation failed.

git-svn-id: 655ff90ec95d1eeadb1ee4bb9db742a3c015d499@1639 8cd8332f-0806-0410-a4b6-96f4b9520244

obeattie/sqlalchemy,obeattie/sqlalchemy,obeattie/sqlalchemy