Suggestion: Clearer Signal Buttons

[Leartin]

In p192comic, in order to support signals that do the same but look different, we employed a system where only one of each type of signal is in the menu with an icon to indicate what it does, rather than how it looks.
Even if this does not clear up how to use them, I think they are at the very least easier to remember and distinguish. I propose using the same/similar icons in p128, to enhance clarity within the pak and across paksets. I attached how they could/would look.

[Vladki]

In pak128.cs we use letters in the corner of the icon (S O P L C E)