added comments

SimplePack/SimplePack.cs

@@ -1,5 +1,4 @@
-using System.Collections;
-using Base58Check;
+using Base58Check;
 
 namespace simplepack
 {
@@ -9,20 +8,25 @@ namespace simplepack
         private string head;
         private string foot;
         public SimplePack(string header, string footer){
+            // Specify human meaningful header/footer string
             head = header;
             foot = footer;
+            // header footer need to be >= 1 len
             if (header.Length == 0 | footer.Length == 0){
                 throw new InvalidSimplePackHeader();
             }
         }
 
         public byte[] decode(string data){
+            // Not valid if it doesn't have head/foot
             if (! data.Contains(head) | ! data.Contains(foot)){ throw new InvalidSimplePackHeader();}
-
             string base58Data = "";
+
+            // Extract the encoded part without header/footer
             for (int i = head.Length; i < data.Length - foot.Length; i++){
                 base58Data += data[i];
             }
+            // Will raise System.FormatException if checksum is not valid (or invalid footer/header)
             return Base58CheckEncoding.Decode(base58Data);
         }