[help-texinfo] Advanced key bindings for stand-alone info

[Robert Ross]

Is there still a way to map keys such as "F1" and "Ctrl-Down" in version 6.0?  
For xterm and mintty in version 5.2, the following worked:

\eOP  get-help-window  # <F1>
\e[1;5B  down-line  # <C-Down>

Setting "key-time" to "0" did not help.  The ability to specify a "keyseq", as 
in "readline", would restore flexibility.

Rob