Improved input and added icon

• Improved keyboard input. Now all characters are supported
• Now you can scroll usingPageUp and PageDown keys or with the mouse wheel.
• The man command has been added.
• The app will show a window icon
• Fixed bug where some commands were not case insensitive.

First release

This is the first working release of the Graphical Postfix Calculator.
You can open it and type help to open the online documentation.