Primecoin HP: Added support for donations via -donationpercentage parameter.
Primecoin HP: Optimize GetBlockWork() by using shifting instead of repeated multiplication.
Speeds up startup slightly.
Optimize repeated bignum multiplications etc by reusing the same BN_CTX. Use lazy initialization inside the CAutoBN_CTX.
log long term average chains per day stat
Merge branch 'master' of https://github.com/mikaelh2/primecoin