Small improvements — El gaucho Martín Fierro Steam update #1405133

Scene 2: It's now possible to move faster by adjusting the bird's flapping speed, but be careful—it gets tired. A hint was added at the beginning of the level to let the player know. Scene 5: A hint was added at the beginning of the level to let the player know which key to press to catch the mosquitoes. Main Menu: It is now possible to select the level using the number keys on the keyboard.