Grid values should have 'custom' option

[ZaxinothDigital]

I was putting together a song, and realized that I needed a 1/5 grid as well as a 1/9 grid. Because there could be many other grid values, however uncommon, that could be wanted, I am suggesting a 'Custom' option, enabling a grid value of any fraction of 1 over any integer, such as 1/5 or 1/9. I am not suggesting values allowed such as 2/5, as this would probably be complicated and does not make much sense. I think this custom grid feature should be added.