Radiator Coaster v2

This is an iteration of [my previous attempt](http://www.thingiverse.com/thing:1766246) at the radiator coaster with a few improvements:

* It's actually the correct size for a coaster now. I actually used an iPhone app upscaled for a bigger phone so when I went around measuring coasters and said 6x6 cm should be good, I was very incorrect. I measured with a ruler this time, and settled on a semi-standard size of 94x94mm.
* The distance of the raised sections to the edge of the coaster is now consistent.