* viper-ex.el (ex-token-list,ex-cmd-execute): Revamped, courtesy
of Scott Bronson.
(ex-cmd-assoc,ex-cmd-one-letr): New functions.
(viper-check-sub,viper-get-ex-command,viper-execute-ex-command):
Deleted functions.
(viper-get-ex-com-subr,viper-ex,ex-mark): Changed to use the new
ex-token-list.