Add starttls for smtp, imap and ftp (#36)

README.md

@@ -31,6 +31,8 @@ meaningful visualisations and consoles.
     - [Configuration file](#configuration-file)
       - [<module>](#module)
       - [<tls_config>](#tls_config)
+      - [<https_probe>](#https_probe)
+      - [<tcp_probe>](#tcp_probe)
   - [Example Queries](#example-queries)
   - [Proxying](#proxying)
   - [Grafana](#grafana)
@@ -152,7 +154,7 @@ modules: [<module>]
 #### \<module\>
 
 ```
-# The protocol over which the probe will take place (http, tcp)
+# The protocol over which the probe will take place (https, tcp)
 prober: <prober_string>
 
 # Configuration for TLS
@@ -160,6 +162,7 @@ prober: <prober_string>
 
 # The specific probe configuration
 [ https: <https_probe> ]
+[ tcp: <tcp_probe> ]
 ```
 
 #### <tls_config>
@@ -188,6 +191,13 @@ prober: <prober_string>
 [ proxy_url: <string> ]
 ```
 
+#### <tcp_probe>
+
+```
+# Use the STARTTLS command before starting TLS for those protocols that support it (smtp, ftp, imap)
+[ starttls: <string> ]
+```
+
 ## Example Queries
 
 Certificates that expire within 7 days: