Simple Program Chooser
A simple program chooser menu to allow one to select a "subprogram" to run. After the "subprogram" finished, the menu will be displayed again. In the menu, the program is selected with button "A", the number of the selected program is shown on the LED matrix. To run a selected program, press button "B". By setting the variable "menu_max" to the number of available "subprograms" and by adding/removing "if selected = <program id>" blocks at the end, the menu could be easily customized.