Added the keyword 'define' to define a compile-time evaluated constant;

Example:
	define PI (Math.pi);
	say PI;

It also works without parentheses with simple objects:

	define str "Hello, World!";
	say str;

	## Dynamic defined array
	define arr [1,2,3];   # this is a dynamic array
	arr[0] = 4;           # not changed
	say arr[0];           # prints: 1

	## Static defined array
	define arr ([1,2,3]); # this is a static array
	arr[0] = 4;           # changed
	say arr[0];	      # prints: 4