Allow ASAN binaries and add some quality-of-life improvements

[ammaraskar]

Contributing these upstream, these are some changes I found useful when testing locally.

• Allows running ASAN instrumented binaries, I've placed instructions on how to do so in the README.

• Stops hardcoding of the seeds/ folder in nn.py

• Binds the socket with SO_REUSEADDR so you don't have to wait for the OS to release the socket if the process crashes.

Please do test locally if you can, I can't be sure that I haven't broken any behavior you were relying on.