Updated dependencies and small mail fixes

- Updated rust nightly
- Updated depenencies
- Removed unicode support for regex (less dependencies)
- Fixed dependency and nightly changes/deprications
- Some mail changes for less spam point triggering

src/config.rs

@@ -557,6 +557,10 @@ fn validate_config(cfg: &ConfigItems) -> Result<(), Error> {
             err!("Both `SMTP_HOST` and `SMTP_FROM` need to be set for email support")
         }
 
+        if !cfg.smtp_from.contains('@') {
+            err!("SMTP_FROM does not contain a mandatory @ sign")
+        }
+
         if cfg.smtp_username.is_some() != cfg.smtp_password.is_some() {
             err!("Both `SMTP_USERNAME` and `SMTP_PASSWORD` need to be set to enable email authentication")
         }