Add option to control whether area-linked nodes must be configured

This should address issue # 261.
Before April 19, 2016, area-linked nodes were required to be listed as nodes in sbbsecho.ini:
http://cvs.synchro.net/cgi-bin/viewcvs.cgi/src/sbbs3/sbbsecho.c?revision=3.6&view=markup
I'm not sure why the change was made to only require that there be a wildmatch for each area-linked node. So just make it a configuration option. <shrug>

Also removed the trailing "..." for every top level menu item in echocfg.