Another kernel scanning optimization
Another kernel scanning optimization

There is no sense of continuous hashing of full 28 bytes sequence because first 24 bytes of kernel are static. Pre-calculate midstate from first 24 bytes instead to avoid unnecessary operations.

~33% performance boost

novacoin-project/novacoin,penek/novacoin,novacoin-project/novacoin,penek/novacoin,byncoin-project/byncoin,elambert2014/novacoin,elambert2014/novacoin,elambert2014/novacoin,fsb4000/novacoin,fsb4000/novacoin,byncoin-project/byncoin,byncoin-project/byncoin,fsb4000/novacoin,byncoin-project/byncoin,fsb4000/novacoin,penek/novacoin,fsb4000/novacoin,byncoin-project/byncoin,novacoin-project/novacoin,novacoin-project/novacoin,novacoin-project/novacoin,penek/novacoin,penek/novacoin,penek/novacoin,byncoin-project/byncoin,elambert2014/novacoin,novacoin-project/novacoin,elambert2014/novacoin,elambert2014/novacoin,fsb4000/novacoin