Fix for acting as master console for some systems

During the Operating System Load Menu display, AOS/VS appears to send a spurious DASHER READ_WINDOW_ADDR command. DasherA now has a half-second timeout on the response to this command to avoid hanging in the protocol and freezing up.

Fix session reconnection and vertical pos. of Set Cursor Address

Various smallish fixes...

• Handle unexpected telnet host disconnect
• Enable reconnection
• Correct Y position in DASHER Set Cursor Address command handling
• Improve logging

Fix building under GNAT 10 / GCC 10

Minor change to Redirector for clean compile and build under version 10 GNAT and GCC.

First release of Ada version!

This is the first release of the Ada rewrite of my DasherQ/J/G/A series of Data General DASHER D200/210 emulators.

I believe it is functionally equivalent or superior to the last version of DasherG (which will no longer be maintained).