Improve hush_scanner and seed node contrib file

contrib/hush_scanner

@@ -16,6 +16,13 @@ print "HOST   P2P  RPC\n";
 while (<>) {
     chomp;
     my $host = $_;
+
+    # skip empty lines
+    next unless $host;
+
+    # skip comment lines
+    next if ($host =~ m/^#/);
+
     my $p2pport = $ENV{P2PPORT} || 18030;
     my $rpcport = $ENV{RPCPORT} || $p2pport + 1;
     my $cmd1  = qq{nc -z -w2 $host $p2pport};

contrib/hush_seed_nodes.txt

@@ -1,3 +1,25 @@
+# This is a list of nodes which hushd attempts to connect to automatically
+# at start up time. You can check to see if they are up/down with:
+# cd contrib; cat hush_seed_nodes.txt | ./hush_scanner
+
+# IP/tor/i2p seeds from src/chainparamsseeds.h
+185.241.61.43
+87.251.76.166
+45.82.68.233
+87.251.76.33
+137.74.4.198
+149.28.102.219
+155.138.228.68
+107.174.70.251
+# hush_scanner uses nc which cannot deal with these
+# 56wqzfj6mhxgsv3h3nh3pdocguogxfxud55libqjhjsdh5alfsko2iqd.onion
+# hushv3h6mbxd2pptj42reko3jcexcgnz5zvp3mqcu6myto3jhhn4yzyd.onion
+# hushv3xvheqh42ms3ld2nh555muscietkib7gycb7s4psbrjsysfywqd.onion
+# iljqq7nnmw2ij2ezl334cerwwmgzmmbmoc3n4saditd2xhi3xohq.b32.i2p
+# [2a0c:b641:6f1:34::2]
+# [2a0c:b641:6f1:c::2]
+
+# Hostname Seeds from src/hush_utils.h
 node1.hush.is
 node2.hush.is
 node3.hush.is