Add initial Date bindings

Doesn't do much, yet, because we can't get the timezone with a plain binding, but it's at least something.

std/assembly/date.ts

@@ -0,0 +1,37 @@
+import {
+  UTC as Date_UTC,
+  now as Date_now
+} from "./bindings/Date";
+
+export class Date {
+
+  @inline static UTC(
+    year: i32,
+    month: i32 = 0,
+    day: i32 = 1,
+    hour: i32 = 0,
+    minute: i32 = 0,
+    second: i32 = 0,
+    millisecond: i32 = 0
+  ): i64 {
+    return <i64>Date_UTC(year, month, day, hour, minute, second, millisecond);
+  }
+
+  @inline static now(): i64 {
+    return <i64>Date_now();
+  }
+
+  private value: i64;
+
+  constructor(value: i64) {
+    this.value = value;
+  }
+
+  getTime(): i64 {
+    return this.value;
+  }
+
+  setTime(value: i64): void {
+    this.value = value;
+  }
+}