Small 1U shelf, refined

Previously I had hacked together a quick little shelf and uploaded it here: https://www.thingiverse.com/thing:6931358

But I thought a number of refinements could be made while practicing some of my OnShape skills. I wanted to make the shelf both a bit faster to print, hopefully a bit stiffer, and with using the technique of making the holes a tear drop shape to make them print better without any need for supports. Rather than start with the previous shelf, I started from scratch and got some experience using the Linear Pattern tool to put in the screwholes and the gaps in the bottom of the rack. I also added an additional rim around the platform, both to stiffen it and to keep things like a Raspberry Pi that I might put on it from sliding off the sides or back. Perhaps this will be of use to others as well.