Iota v0.3.0 final release

[solidstate1991]

D language native replacement of SDL, SFML, Raylib, GLFW, etc., 
iota version 0.3.0 has been released.

- Basic audio output works. Main things missing are handling 
audio device disconnections and device selection on Linux not 
working. By using `createLowLevelThread`, it works well with GC.
- Input device handling works, there's raw input and controller 
support through XInput for Windows. The same for Linux will come 
later.
- OpenGL works, but only basic OS-tied functionality is exposed 
at the moment, and some will be a bit troublesome, which will be 
more difficult for Windows due to the nature of how OpenGL works 
there.
- Basic windowing works, icons and window styling (removal of 
window decorations, etc.) will come later.
- No Wayland support at the moment, if someone wants to take it 
up, I'll let them.
- No Mac support due to lack of hardware on my own end. I'll let 
others to do it instead, especially due to the Metal API.
- Android support is planned by me.
- At one day, alternative runtime and Vulkan support will be 
added.