Tile grid subdivisions

Hello :)

I've been using PyxelEdit for quite a while now but I finally made an account on the forum today.

Systems like the Gameboy and NES were limited to 8x8 or 8x16 pixels for physical tile sizes, but the graphical tilesets the artists created were often 16x16 using groups of the smaller tiles. I've been setting up PyxelEdit with 8x8 grids for most of my work, but creating tilesets with these smaller pieces and building them into the larger chunks can get a little tedious when putting everything together. I like to keep my work restricted to the old system constraints, so making sure things like the number of colors per "physical" tile is right is very important.

I'm hoping you can add a sub-grid feature to PyxelEdit. Nothing would be tied to it, it would only be a visual reference. The ability to set up the document using a 16x16 grid so I can draw my bigger tiles, while having gridlines every 8 pixels (user-defined x,y values would be the best option!) to help guide how many colors are in the "physical" tile would be a huge help.

Thanks and keep up the great work on PyxelEdit!