added rules for operators

[Servostar]

Added rules for operators. These include:

• Arithmetic (+,-,*,/) + negate
• Logical (Equals)
• Boolean (And, Or, Xor, Not)
• Bitwise (And, Or, Xor, Not)

Operators have corresponding associativity , unary operators such as Not and Negate additionally have greater precedence.

[flixm16]

what about less and greater, less equals and greater equals? what about not equals?

[Servostar]

Implemented greater, less operator. Since no tokens for >=, <= or != exist, these operators won't be implemented