README: update for v0.4 release

- Switch to a Github version of README
- Add "How to use" section
- Fix "How to build on Linux" section, adding dependencies
- Add "How to build on Windows" section
- Add changelog for v0.4 release

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>

HID: add support for one device

Change behavior in case of no_app.

Actually when starting the device in accessory mode with no application
required (AOA 2.0 and higher only), the android device is recognized
as an ALSA sound card. Therefore a "arecord -f cd | aplay -f cd"
allows users to listen to streamed music.

Alpha release v0.1