Also list the capnames with which the escape sequences could be
read from Terminfo, and the ECMA-48 interpretations of the bytes
(parenthesized if they seem unrelated to the keys). This is in
preparation for fixing bug 96.
decode_terminal_escape_sequence() used to handle both, but
there is now a separate decode_terminal_application_key()
for ESC O. I have not yet edited decode_terminal_escape_sequence();
there may be dead code in it.
If there is e.g. ESC [ in the input buffer, combine that to Alt-[.
Check the first character too; don't blindly assume it is ESC, as
it can be NUL as well. Note this means you can no longer activate
the main menu by pressing Ctrl-@ (or Ctrl-Space on some terminals).
Otherwise, the timeout could cause ELinks to resume reading from
the terminal device while another process is still using it.
This actually happened in a test.
On entry to some functions that could resume reading from the device,
assert that the terminal has not been blocked.
