CalcApp Calculator Application

Version 2.1 : Add several functions and function keyboard. Variable assignment is now possible and comparative as well as logical operators are implemented. Math engine becomes developed to line interpreter.
Version 2.2 : Statements can be exported to external file and importable from the text file. Many geometrical properties of the structural shape are supported. User may choose functions for the structural properities.
Version: 2.3:
Change compile version to 14