Second build of rev B

As Kevin mentioned yesterday, we were able to build a second rev B Titan using the ECP5 that we reclaimed from our rev A build. I'm still working to get the PCI Express interface to enumerate, but the build went well as the video above shows.

We've found a few clear errors in the PCB that we need to fix and we've already started some preliminary work on rev C. I'll outline what we found as soon as we have a more complete list.