Thumb Format 15 opcodes deccoding implemented
Change offset operand to its actual value instead of adding PC for Format 6: Load PC relative
Thumb Format 16 opcodes deccoding implemented (invalid cond = 14 checked)
Thumb Format 17 opcodes deccoding implemented
Thumb Format 18 opcodes deccoding implemented
Remove explicit undefined opcode test
Invalid Thumb Format 18 opcodes deccoding implemented
Thumb Format 19 opcodes deccoding implemented (with invalid check)