Add `iregister-copy-to-register-kill-ring-save'.
Update doc-strings and documentation.
Rename `iregister-kill-copy-to-register'.

Rename `iregister-kill-copy-to-register' to
`iregister-copy-to-register-kill'.
Rename `iregister-delete-copy-to-register'.

Rename `iregister-delete-copy-to-register' to
`iregister-copy-to-register-delete'.
Rename `iregister-delete-append-to-latest-register'.

Rename `iregister-delete-append-to-latest-register' to
`iregister-append-to-latest-register-delete'.
Update documentation.
Rename `iregister-kill-append-to-latest-register' to
`iregister-append-to-latest-register-kill'.
Add utility function.

Add `iregister-point-or-text-to-register-1' function.
Rename function.
Update doc strings.
Update documentation.
Bump version.