* viper.el (viper-remove-hooks): remove some additional viper hooks
when the user calls viper-go-away.
(viper-go-away): restore the default of default-major-mode.
Save the value of default-major-mode before vaperization.
* viper-cmd.el: Replace error "" with "Viper bell".
* viper-ex.el: Replace error "" with "Viper bell".
* ediff-util.el (ediff-make-temp-file): use the coding system of the
buffer for which file is created.