Use 0 for all secondary mapping of the table

Need to update dbbuilder to implement mechanism suggested by https://github.com/Cangjians/ibus-cangjie/issues/77#issuecomment-269938845 (solution B). The aim is to remove the disturbance of all non-standard mapping to the order in Quick input method and resolve https://github.com/Cangjians/ibus-cangjie/issues/77.