Added note for possible improvement

Headers/Vigenere.hpp

@@ -11,6 +11,7 @@
 #include <string>
 #include <vector>
 
+///TODO: Might be able to make encoding and decoding faster for longer messages by actually using a grid of alphabets (Caesar Ciphers)
 class Vigenere{
 private:
 	std::string inputString;    //This is the string that you want to encode or decode