Refactor everything

We now hijack existing system functions to integrate with `WinMgr`,
instead of `Spawn`ing our own `SaphirTask`.

Also, you can now use `Saphir(Bool)` to toggle enable/disable the
features.

There is a global var `saphir` which values are set by `Defaults.HC` for
colors and other behaviors; these values can be changed at any time.

Saphir/Main.HC

@@ -0,0 +1,16 @@
+I64 Saphir(Bool enable = TRUE)
+{
+    if (enable == saphir.enabled) {
+        return enable;
+    }
+    fn_patch(&Blink, &saphir_Blink, enable);
+    fn_patch(&DocBorder, &saphir_DocBorder, enable);
+    // fn_patch(&DocBorderLstDraw, &saphir_DocBorderLstDraw, enable);
+    fn_patch(&DrvTextAttrGet, &saphir_DrvTextAttrGet, enable);
+    saphir_cursor(enable);
+    saphir_keydev(enable);
+    if (!enable) {
+        DCFill;
+    }
+    saphir.enabled = enable;
+}