Enable --generate-to option (was --coinbase-addr) to work with non-default goals
proxy: Minimise minimum difficulty for proxy clients
Move MAX_*_INTENSITY stuff to driver-opencl.h
opencl: Reintroduce independent intensity setting internally
Core only: Partially move most of opt_scrypt to mining_goal
proxy: Avoid assumptions about mining algorithm at initialisation
Replace cgpu.min_nonce_diff with drv.drv_min_nonce_diff(cgpu, malgo)
cpu: Support for per-work mining algorithms
WIP