v2.1:

- added "-i" option for adjusting mining intensity and CPU usage.
- improved speed for high intensity mode ("-i 2"), about 60H/s on stock 390X, 50H/s on stock 280X.
- since nicehash cannot upgrade their ddos protection, now "-allpools 1" is required for this pool.

PS. OpenCL API uses CPU to wait response from GPU in high intensity mode so it's not easy to fix this issue completely, currently you can use "-i 0" option if you have low-end CPU.