Implement IXYI math

[pushfoo]

• [x] 8xy1 - Set Vx = Vx OR Vy.
• [x] 8xy2 - Set Vx = Vx AND Vy.
• [x] 8xy3 - Set Vx = Vx XOR Vy.
• [x] 8xy4 - Set Vx = Vx + Vy, set VF = 1 if sum greater than 255
• [x] 8xy5 - Set Vx = Vx - Vy, VF = 1 if Vx > Vy, else VF = 0
• [x] 8xy6 - shift right . If the least-significant bit of Vx is 1, then VF is set to 1, otherwise 0. Then Vx is divided by 2.
• [x] 8xy7 - If Vy > Vx, then VF is set to 1, otherwise 0. Then Vx is subtracted from Vy, and the results stored in Vx.
• [x] 8xyE - shift left - If the most-significant bit of Vx is 1, then VF is set to 1, otherwise to 0. Then Vx is multiplied by 2.