[Xastir] Added a Logging Indicator

[Jim Chandler]

Xastir does not currently have any management of log file size.  You can
fill up your HD if you aren't careful (I know from past experience.)  As
an interim measure, I recently promoted code that adds a logging indicator
box at the bottom of the screen.  It indicates whenever at least one
logging file is currently active (net, tnc, wx and/or igate).  Enjoy.

Jim
N0VH