Patches from Eric NO3M to so2sdr.cpp and so2sdr_key.cpp:

1. Quick call dump S/P: <space> in sprint mode switches mode to
s/p+sends call, but will only move to exch field automatically if call
entered > 3 characters, assuming call entry is not complete (rare to
hear 3 letter calls in sprint).  Also stays in call field if dupe
(same as original).  After completing a partial call entry, an
additional <space> will move focus to exch.  Upon moving to exchange,
a space at the end of any prefill is added, ready to appended info w/o
another <space>.  Example flows, assuming prefilled name and state:

n4ogw<space>10<enter>
n4<space>ogw<space>10<enter>
<space>n4ogw<space>10<enter>

2. Enter in sprint s/p will log QSO when exchange is sent (per above),

3. If 2nd radio CQ is active on inactive radio, <enter> in call field
on active radio will send 2nd radio CQ again (F1 message) if active
radio is in CQ mode and call field is empty.  <enter> is basically
captured from active radio, indicated by the existing "CQCQCQ" message
on the 2nd/inactive radio, until <esc> to clear 2nd radio CQ or call
is entered and moved to inactive radio as already.

<enter> is normal for active radio S/P.  If QSO is logged (forced dupe
or not), 2nd radio CQ is cleared for jump ball.

4.  If exch field is not validated and exch has already been sent,
ready to log, Shift+F2 (?) message will be sent on <enter>. Hitting
<enter> to log an invalid exchange is more or less operator error or
intentional, since other options are already in place: force log with
cntrl-<enter> or \ or shift-<enter>, use shift-F3++ for specific
fills, or operator just wipes exch field and <enter> to get complete
fill.

5. A space is added to end of prefilled exchange in CQ mode when focus
shifts there, eliminating entering <space> to append info

6.  prefixCheck to keep displayed info on active radio in S&P when 2nd
radio CQ is active and <tab> and <space> prefills were not populating
exchange field under certain conditions.