Sv2 Miner w/ acceleration

[average-gary]

Consider stratum-mining/stratum#1901 for demos

[vnprc]

+1 great idea. This would make testing with the CPU miner a much nicer process. I currently have to wait a few minutes for shares to start appearing.

Nowadays I just keep a bitaxe plugged in on my desk with my dev environment as the first upstream profile but this would be great for travelling and demos like Sjors says in the ticket.