TN3270 conversation type

The TN3270 connector checks the settings below periodically; changes affect current and new conversations.

[logging]
client-close=client-close-logging
[Operation]
default-terminal-type=terminal-type-name
Timeout=number-of-seconds
TN3270E=negotiation-type
[Trace]
trace=control-flow-trace
data=data-trace
length=trace-length
sem=send-semaphore-trace
file=trace-filename