GB Studio Text Entry

I needed a text entry method for GB Studio, but I didn't like any of the ones I found online, so I decided to make my own. There's more information on how it works in the comments of the project, but I'll give a brief description.

TL;DR: Each letter has its own number. When you press A that number is set to the letter pressed.

How this works is that the input directions also add and subtract to $Letter.  This gives each letter a number starting at 1 and wrapping around each row. Example: A=1, B=2, N=13, O=14.

Then when A is pressed it sets the value of $Letter to the first available slot by increasing the frame count of the L variables. It then changes the N variables to the letter selected.