{gfx,examples}: update all to new mach.Core module API

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

examples/sprite/main.zig

@@ -1,17 +1,18 @@
-// TODO(important): review all code in this file in-depth
-
-// Experimental ECS app example. Not yet ready for actual use.
 const mach = @import("mach");
 
-const Game = @import("Game.zig");
-
-// The list of modules to be used in our application. Our game itself is implemented in our own
-// module called Game.
+// The global list of Mach modules registered for use in our application.
 pub const modules = .{
-    mach.Engine,
+    mach.Core,
     mach.gfx.Sprite,
     mach.gfx.SpritePipeline,
-    Game,
+    @import("Game.zig"),
 };
 
-pub const App = mach.App;
+// TODO(important): use standard entrypoint instead
+pub fn main() !void {
+    // Initialize mach.Core
+    try mach.core.initModule();
+
+    // Main loop
+    while (try mach.core.tick()) {}
+}