Does all of the low level setting up of a desktop application so you don't have to.
To use it, your main function should look something like this:
using EV3devKitDesktop;
static int main (string[] args) {
GtkApp.init (args);
// Program-specific initialization which includes something
// that calls GtkApp.quit () when the program is finished.
GtkApp.run ();
// any additional cleanup if needed before application exits.
return 0;
}