My previous commit failed in the travis-ci environment despite passing on my
local computer. This appears to be due to expect timing out looking for the
expected input. See if increasing the expect timeout slightly fixes the
problem.
Introduce a "fish_escape_delay_ms" variable to allow the user to configure the
delay used when seeing a bare escape before assuming no other characters will
be received that might match a bound character sequence. This is primarily
useful for vi mode so that a bare escape character (i.e., keystroke) can
switch to vi "insert" to "normal" mode in a timely fashion.
