add cty3126, enable spot cache as default

Changes

@@ -1,3 +1,16 @@
+18Nov21=======================================================================
+1. Add a dx spot cache which will store 2 days worth (configurable) of spots.
+   This is then used by the vast majority of simple sh/dx queries without 
+   using a sub process. A simple sh/dx is any sh/dx that does not have an
+   "expression" such as "sh/dx g1tlh". So "sh/dx", "sh/dx 200", "sh/mydx" will
+   always run in the main program via the cache. Certain client programs (no
+   names, no pack drill) will notice the difference immediately. It's also a
+   bit snappier.
+2. set/badspotter or set/badnode will work for RBN input. 
+3. RBN input with invalid QRGs will be dropped with a nice friedly message
+   rather than a scary exception message about multiplication thrown by one 
+   of the libraries that I use. 
+4. Added CTY-3126 prefixes.
 15Jul21=======================================================================
 1. Fix long standing bug in crontabs that commands with " rather than ' around
    strings could cause those commands not to work. 

perl/Spot.pm

@@ -70,7 +70,7 @@ $totalspots = $hfspots = $vhfspots = 0;
 $use_db_for_search = 0;
 
 our %spotcache;					# the cache of data within the last $spotcachedays 0 or 2+ days
-our $spotcachedays = 0;
+our $spotcachedays = 2;
 
 
 our $readback = 1;