Update code style

Limit source code to 80 chars, and declare functions return type and
modifiers on a separate line.

This allows to avoid very long lines, and all function names are
aligned.

(We do this on VLC, and I like it.)

app/src/device.h

@@ -10,6 +10,7 @@
 #define DEVICE_SDCARD_PATH "/sdcard/"
 
 // name must be at least DEVICE_NAME_FIELD_LENGTH bytes
-SDL_bool device_read_info(socket_t device_socket, char *name, struct size *frame_size);
+SDL_bool
+device_read_info(socket_t device_socket, char *name, struct size *frame_size);
 
 #endif