Update README.md and add deprecation to methods that panic.

Author: speps

README.md

@@ -23,23 +23,36 @@ func main() {
     h := hashids.NewWithData(hd)
     e, _ := h.Encode([]int{45, 434, 1313, 99})
     fmt.Println(e)
-    d := h.Decode(e)
+    d, _ := h.DecodeWithError(e)
     fmt.Println(d)
 }
 ```
 
 ### Test results
 
 ```
-=== RUN TestEncryptDecrypt
---- PASS: TestEncryptDecrypt (0.00 seconds)
-    hashids_test.go:21: [45 434 1313 99] -> woQ2vqjnG7nnhzEsDkiYadKa3O71br -> [45 434 1313 99]
-=== RUN TestDefaultLength
---- PASS: TestDefaultLength (0.00 seconds)
-    hashids_test.go:47: [45 434 1313 99] -> 7nnhzEsDkiYa -> [45 434 1313 99]
-=== RUN TestCustomAlphabet
---- PASS: TestCustomAlphabet (0.00 seconds)
-    hashids_test.go:74: [45 434 1313 99] -> MAkhkloFAxAoskax -> [45 434 1313 99]
+=== RUN   TestEncryptDecrypt
+--- PASS: TestEncryptDecrypt (0.00s)
+        hashids_test.go:22: [45 434 1313 99] -> woQ2vqjnG7nnhzEsDkiYadKa3O71br -> [45 434 1313 99]
+=== RUN   TestEncryptDecryptInt64
+--- PASS: TestEncryptDecryptInt64 (0.00s)
+        hashids_test.go:49: [45 434 1313 99 9223372036854775807] -> ZvGlaahBptQNfPOuPjJ51zO3wVzP01 -> [45 434 1313 99 9223372036854775807]
+=== RUN   TestEncryptWithKnownHash
+--- PASS: TestEncryptWithKnownHash (0.00s)
+        hashids_test.go:75: [45 434 1313 99] -> 7nnhzEsDkiYa
+=== RUN   TestDecryptWithKnownHash
+--- PASS: TestDecryptWithKnownHash (0.00s)
+        hashids_test.go:92: 7nnhzEsDkiYa -> [45 434 1313 99]
+=== RUN   TestDefaultLength
+--- PASS: TestDefaultLength (0.00s)
+        hashids_test.go:115: [45 434 1313 99] -> 7nnhzEsDkiYa -> [45 434 1313 99]
+=== RUN   TestMinLength
+--- PASS: TestMinLength (0.00s)
+=== RUN   TestCustomAlphabet
+--- PASS: TestCustomAlphabet (0.00s)
+        hashids_test.go:150: [45 434 1313 99] -> MAkhkloFAxAoskax -> [45 434 1313 99]
+=== RUN   TestDecryptWithError
+--- PASS: TestDecryptWithError (0.00s)
 PASS
 ```
 

hashids.go

@@ -197,6 +197,7 @@ func (h *HashID) EncodeInt64(numbers []int64) (string, error) {
 	return string(result), nil
 }
 
+// DEPRECATED: Use DecryptWithError instead
 // Decode unhashes the string passed to an array of int.
 // It is symmetric with Encode if the Alphabet and Salt are the same ones which were used to hash.
 // MinLength has no effect on Decode.
@@ -223,6 +224,7 @@ func (h *HashID) DecodeWithError(hash string) ([]int, error) {
 	return result, nil
 }
 
+// DEPRECATED: Use DecryptInt64WithError instead
 // DecodeInt64 unhashes the string passed to an array of int64.
 // It is symmetric with EncodeInt64 if the Alphabet and Salt are the same ones which were used to hash.
 // MinLength has no effect on DecodeInt64.