The right-click is almost useless on Android, so use it to turn the
screen on.
Add a new control event type (command) to request the server to turn the
screen on.
Replace screenrecord execution by manual screen encoding using the
MediaCodec API.
The "screenrecord" solution had several drawbacks:
- screenrecord output is buffered, so tiny frames may not be accessible
immediately;
- it did not output a frame until the surface changed, leading to a
black screen on start;
- it is limited to 3 minutes recording, so it needed to be restarted;
- screenrecord added black borders in the video when the requested
dimensions did not preserve aspect-ratio exactly (sometimes
unavoidable since video dimensions must be multiple of 8);
- rotation handling was hacky (killing the process and starting a new
one).
Handling the encoding manually allows to solve all these problems.
