Add console tetris demo

apps/zigtris/src/main.zig

@@ -0,0 +1,41 @@
+const uvm = @import("uvm.zig");
+
+const mibu = @import("mibu");
+const zigtris = @import("zigtris");
+var nextEvent:mibu.events.Event = .none;
+
+const console = @import("console.zig").getWriter();
+
+export fn main() void {
+    var gameRunning = true;
+    var lastUpdate:u32 = 0;
+
+    zigtris.gamesetup(console, uvm.millis()) catch |err| {
+        _ = console.print("err {any}\n", .{err}) catch 0;
+        _ = console.flush() catch 0;
+        return;
+    };
+
+    while(gameRunning) {
+        const now = uvm.millis();
+        if (uvm.getch()) |key| {
+            switch(key) {
+                ' ' => nextEvent = mibu.events.Event{.key = .{.code = .{.char = ' '}}},
+                'a' => nextEvent = mibu.events.Event{.key = .{.code = .left}},
+                'd' => nextEvent = mibu.events.Event{.key = .{.code = .right}},
+                'w' => nextEvent = mibu.events.Event{.key = .{.code = .up}},
+                's' => nextEvent = mibu.events.Event{.key = .{.code = .down}},
+                'q' => gameRunning = false,
+                else => {},
+            }
+        }
+
+        if (now > lastUpdate + 100 or nextEvent != .none) {
+
+            lastUpdate = now;
+            gameRunning = zigtris.gameloop(console, now, nextEvent) catch false;
+            nextEvent = .none;
+            _ = console.flush() catch 0;
+        }
+    }
+}