some restructuring due to the recent changes to usingnamespace.
also cleaned up some deprecated stuff from raylib 3.7.
- appended the contents of raylib-wa.zig into raylib-zig.zig
- using raylib functions requires `const rl = @import("raylib");`
(and accesing the identifiers inside rl, like `rl.InitWindow`)
only the basic_window example was updated, and it looks like it crashes
on keyboard inputs.
many thanks to @nektro :)
