Day 4 - Board display

First day of programming. I removed the old not-yet-working space invader from the project and started implementing a tiled board display.

What the project looked like when I picked it up from the dust:

What I had at the end of the day:

I'm using an old project that was a proof of concept of a WebAssembly transpiler.
I only have the basics pieces to work with:

• a simple `for` loop (I can't nest them, gotta be creative with that limitation...)
• local variables in functions, but they must be declared at the beginning of the function definition
• somewhat handy way to setup initial data and keep flags to some addresses (instead of relying on comments and magical values) using a hash table
• only 32bits integers
• `(if cond body ...)` and `(if cond (then body ...) (else body ...)`
• no way of loading images, gotta write them by hand in binary
• async interface with javascript (js can call wasm and wasm can call js)
• a simple FPS limited loop in js