Redefine padding as a struct to make the returned values more clear.
Redefine decode-padding to operate on a string instead of
string-stream.  The new code is shorter and seems a bit more obvious.
Add a strings-and-delays function to decompose a command into command
characters and delay specification lists.  Change tputs to have key
parameters and to return a strings-and-delays list when stream is
nil instead of printing.
Remove the getter for stream baud rate.  This is now an input parameter.