Implement LD (NN), SP; fix LD HL,SP+d and ADD SP,d
Implement LD (NN), SP; fix LD HL,SP+d and ADD SP,d

The carry and half-carry bits for SP addition are calculated as an
unsigned addition of the lower 8 SP bits and the immediate.

binji/binjgb,binji/binjgb,binji/binjgb