Add entry to snapscraft yaml; cleanup bash header

multinode-demo/simple-client.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# usage: $0 <rsync network path to solana repo on leader machine> <number of nodes in the network???>"
+# usage: $0 <rsync network path to solana repo on leader machine>"
 #
 
 here=$(dirname "$0")

snap/snapcraft.yaml

@@ -47,6 +47,8 @@ apps:
     command: solana-mint-demo
   client-demo:
     command: solana-client-demo
+  simple-client-demo:
+    command: solana-simple-client-demo
 
   daemon-validator:
     daemon: simple