Fix base64 decoding issue with unpack m

Author: bjfish

library/base64/decode64_spec.rb

@@ -22,4 +22,8 @@
   it "returns a binary encoded string" do
     Base64.decode64("SEk=").encoding.should == Encoding::BINARY
   end
+
+  it "decodes without padding suffix ==" do
+    Base64.decode64("eyJrZXkiOnsibiI6InR0dCJ9fQ").should == "{\"key\":{\"n\":\"ttt\"}}"
+  end
 end