Updated picard and qr things

qr_code_crypto/src/lib.rs

@@ -36,7 +36,13 @@ impl CryptoInvoice for MoneroInvoice {
     }
 
     fn validate(self) -> bool {
-        unimplemented!();
+        // TODO - actually do this properly - I think there's a checksum to check
+        //  and should check the first chars are 4 or 8... and some more things
+        //  probably only supper standard addresses too
+        if self.address.len() != 95 {
+            return false;
+        }
+        true
     }
     fn address(self) -> String {
         self.address