Move the code handling user input from scrcpy.c to a separate file,
screencontrol.c.

Move the code to read the initial device info from scrcpy.c to a
separate file, device.c.

The file scrcpy.c contains too many different things in addition to the
main logic, so move the screen code to a separate file, screen.c.

The struct decoder is defined in decoder.h.

For naming consistency, define the struct controller in controller.h.

Expose scrcpy version via -v or --version.

The skip_frames flag was a non-configurable runtime flag. Since it is
not exposed to the user, there is no need for a (possible) runtime cost.

For testing purpose, we still want it to be configurable, so make it a
compilation flag.

Make meson generate config.h with configured values.

We encounter some problems with SDL2_image on MSYS2 (Windows), so
implement our own XPM parsing which does not depend on SDL_image.

The input XPM is considered safe (it's in our source repo), so do not
check XPM format errors. This implies that read_xpm() is not safe to
call on any unsafe input.

Although less straightforward, use SDL_CreateRGBSurfaceFrom() instead of
SDL_CreateRGBSurfaceWithFormatFrom() because it is available with SDL
versions older than 2.0.5.

Add a bugdroid icon loaded from an XPM.

Rename scrcpy.c to main.c (this file handles the command line parsing),
and screen.c to scrcpy.c (it exposes the entry point scrcpy()).

To lighten screen.c, move start_server() and stop_server() to a separate
file.

Test serialization of the 4 types of events (keycode, text, mouse,
scroll).

Test our custom string handling functions.

To control the device from the computer:
 - retrieve mouse and keyboard SDL events;
 - convert them to Android events;
 - serialize them;
 - send them on the same socket used by the video stream (but in the
 opposite direction);
 - deserialize the events on the Android side;
 - inject them using the InputManager.

Move unix/ and win/ to sys/, so that we can use android/ for android
headers without confusion.

This duplicates chars in the final binary.

Start a new clean history from here.