Use "conversion" instead of "cast", per spec

Closes #200

examples/base64-encoding/base64-encoding.go

@@ -17,7 +17,7 @@ func main() {
     // Go supports both standard and URL-compatible
     // base64. Here's how to encode using the standard
     // encoder. The encoder requires a `[]byte` so we
-    // cast our `string` to that type.
+    // convert our `string` to that type.
     sEnc := b64.StdEncoding.EncodeToString([]byte(data))
     fmt.Println(sEnc)
 

examples/base64-encoding/base64-encoding.hash

@@ -1,2 +1,2 @@
-e57f5be3a796261fb4a55cdb0580a254e14b4930
-t6rFm2x4Yr
+c20da14820b656c867790f2e99bc37140babca8c
+y_QTcqdkvZh