Make smeared timestamp creation non-async

Using atomic operations instead,
so create_smeared_timestamp() can be used in sync functions,
such as SQL transactions.

src/lib.rs

@@ -92,6 +92,7 @@ mod smtp;
 mod socks;
 pub mod stock_str;
 mod sync;
+mod timesmearing;
 mod token;
 mod update_helper;
 pub mod webxdc;