Preparing skeleton for proper imgui support.

I originally wanted to reference Ryan's UI series along with the RAD Debugger codebase, but that ended up being too convoluted of a route. Instead, I moved on to just doing a deep dive on imgui content I could find to learn from and associated libraries available. I collected my notes so far in this repo [IMGUI_Notes](https://github.com/Ed94/IMGUI_Notes).

For now I have the base scaffolding datatype wise for the prototype ui.

code/host/memory_windows.odin

@@ -129,3 +129,14 @@ arena_init_static :: proc(arena: ^virtual.Arena, base_address : rawptr,
 
 // END WINDOWS CHECK WRAP
 }
+else
+{
+	// Fallback to regular init_static impl for other platforms for now.
+
+	arena_init_static :: proc(arena: ^virtual.Arena, base_address : rawptr,
+		reserved    : uint = virtual.DEFAULT_ARENA_STATIC_RESERVE_SIZE,
+		commit_size : uint = virtual.DEFAULT_ARENA_STATIC_COMMIT_SIZE
+	) -> (err: virtual.Allocator_Error) {
+		return virtual.arena_init_static( arena, reserved, commit_size )
+	}
+}