Added the ':' method mark to return the self variable after a method is applied on the stored object;
Improved the '!' method mark. Now, the self variable is returned;
Array.rotate no longer modifies the array in-place;
File.open_* can take an obtional argument which must be a Variable::Ref object; When a variable ref is passed, the filehandle is assigned to variable and a boolean value is returned;
Some methods and aliases has been added across objects;