parser.py: Extending grammar to parse less than
simulator.py: Implemented less than op code
parser.py: Extended grammar to parse less than equals
simulator.py: Implemented less than equals op code
parser.py: Extended grammar to parse greater than equals
simulator.py: Implemented greater than equals op code
parser.py: Extended grammar to parse comparison operator
simulator.py: Implemented comparsion (equals) op code
parser.py: Extended grammar to parse not equals operator
simulator.py: Implemented not equals op code