(tpu-original-global-map) Variable deleted.
(tpu-control-keys-map) New keymap variable.
(tpu-set-control-keys) Use tpu-reset-control-keys rather than
setting keymapping directly.
(tpu-reset-control-keys) Use tpu-control-keys-map instead of tpu-global-map.
(tpu-edt-on): Activate the tpu-global-map.
(tpu-edt-off): Deactivate the tpu-global-map.