[IMP] app, compiler: introduce t-out

t-out automatically escaped content when it is a string not marked
with the `markup` function

t-out renders the raw content if it is a Block, or if it has been marked
with the `markup` funtion.

t-esc has been kept since it is safe and is optimized to render text nodes.

all t-raw calls are in fact the same as t-out.

src/reactivity.ts

@@ -128,7 +128,9 @@ function isTrackable(value: any): boolean {
     value !== null &&
     typeof value === "object" &&
     !(value instanceof Date) &&
-    !(value instanceof Promise)
+    !(value instanceof Promise) &&
+    !(value instanceof String) &&
+    !(value instanceof Number)
   );
 }