Unfortunately, easymesh code still relies heavily on its specifics, so I’m
letting it live as lol::easy_array for the near future. But it’s going away.

This is the first step to getting rid of lol::array in favour of std::vector.

Does not work very well because of CORS restrictions in browsers.

Rename “channels” to “tracks” when talking about the mixing channels, to
avoid confusion with channels in the context of mono/stereo/5.1. Also allow
conversions between various formats and frequencies.

To do: allow to query the current audio device’s preferred frequency when
the client application is able to send the best possible data.

Executables that use libbullet are now 1 MiB smaller (stripped!).

Now we can call functions that need to access GPU resources explicitly
on the draw thread.

This lets us get rid of m_autorelease and m_destroy and we’ll be able
to implement init_game/init_draw later, for stuff that must happen
on the render thread.

Controller::WasKeyReleasedThisFrame() is now keyboard->key_released() so
there is usually no need for a controller. They will completely disappear
when joystick axis binding has been ported to InputDevice.