Update lib/SQL/Relation.php
Update lib/SQL/Relation.php

1) more allowed join types
2) throw exception with additional info if selected join type is not allowed
samratcis/atk4,svisystem/atk4,xepan/atk4,svisystem/atk4,atk4/atk4,atk4/atk4,atk4/atk4,samratcis/atk4,svisystem/atk4,atk4/atk4,xepan/atk4,samratcis/atk4,xepan/atk4