Fixed enter function
Added functions related to Variable Declarations
Fixed tab size 4 and tab to space
Added scope stack (Added scope stack entry struct)
Added scope stack and Added print statement into each productions to debugging
Added struct declaration
Added function declarations
Added type check and type compatible (~ing)
Added string const decl and Added scope stack for struct, Added some error check code
Fixed print error line num, Added struct assignment checking
Added unary &, unary * operator syntax, Fixed LValue assignment checking
Added unary -, unary &, INCOP, DECOP type checking
Fixed relop, equop type checking
Added Logical Operator operand checking