update reference link per #119 and use more consistent 'Chip-8' terminology throughout the manual.
update reference link per #119 and use more consistent 'Chip-8' terminology throughout the manual.

james0x0A/Octo,JohnEarnest/Octo,JohnEarnest/Octo,james0x0A/Octo,JohnEarnest/Octo,JohnEarnest/Octo,JohnEarnest/Octo