- Global Error 3 (wrong contrller answer) treating changed. Now,
as for all the rest errors, device goes to FAULT only when three
identical errors in a row occur. To do this, I had to wrap all
requests in "do..while" cycle (ADC request even in two cycles).
- test_message command tested and still works =)
- Some line transfers are added to better show lines at 4:3 moni.

Now all data from gun controller are requested with update command.
Coolers_status command removed, ADC requests code removed from
attribute related methods.

Should be tested with real controller

  Sometimes controller was replying with the Data Error 5 message.
  Logic analyzer studies have shown that this occues when some
delay between the control message bytes appears.
  The only reason (except internal hardware problems) was tcdrain()
before each control message byte sending. In this commit tcdrain()
(which waits until the transmit buffer is empty) is placed only
before the first control message byte. And it seems that no more
Data Error 5 is seen.

- Port name is now specified in "port" device property

Expression was calculated as integer until the first double value
(i.e. until the very end).
Now ADC result still slightly differs from emmulator settings, but
it's OK (14 bits rounding restriction).

Expression was calculated as integer until the first double value
(i.e. until the very end).
Now ADC result still slightly differs from emmulator settings, but
it's OK (14 bits rounding restriction).

(due to oscilloscope experiment with the old version)

By some reason result depends on the position of the "sign" variable in
the expression.

When controller receives request to change any Vref, it should
return the value it received. If this value does not correspond
to the send value, Global error 3 occures.

- Data errors: controller sends 2-byte message with error code
- Global error 2: the same, but 2-byte meassage does not correspond to
any of 7 codes controller can send

- Added check for Global Error 1 (no answer from gun controller)
- Added "ErrorsReset" command
- Added description for "CoolersStatus" command
- Removed "Serial" property

- code shortened (for cycle instead of 4 separate code blocks)
- 75 us delay added at the end (as in the corresponding DOS program)

Now program sends new command to the controller only when the transmit
buffer is empty.