Update TODO.md

TODO.md

 1. Finish kicad design and select values for LED-resistors. 
 2. Set up PCB design to make it look decent and create a reasonable placement for components. 
+https://www.reddit.com/r/MouseReview/comments/isist1/trimming_guide_for_the_g305_pcb_as_used_in_my/
 3. Finish bill of materials, when PCB is completely finished.
 4. Solder and hardware stuff, once components are here. 
 5. Mouse buttons, left, right and wheel (Tobias)