Basic functionality of Softshell works! In the image above, you can see the app (Cocoa-rtl-sdr is the old name) on the right. I didn't even have the text boxes wired in yet for the sample rate and center frequency, because I was so excited that it was working. The samples from the receiver are transported into GNU radio over TCP where a simple FFT is being performed. Notice that all the extra blocks needed for the original rtl-sdr aren't needed, because I'm doing all of the uchar to float conversion inside of Softshell.
The code that's available on GitHub was hacked together with some network code that I can't release right now, but I'm going to move it over to code that I can use soon.
Here's a pre-compiled application for those that don't feel like compiling it: