Created initial SMTP handlers.

__SMTP_HELO.h

@@ -0,0 +1,19 @@
+     //---------------------------------------------------------------------------
+      // HELO command request handling.
+      //---------------------------------------------------------------------------      
+
+      if(command(input) == "HELO") {
+
+         if(input.length() > 5) {
+            string hostName = input.substr(5);
+         }
+
+         else {
+
+            // TODO: Provide error message demanding identity here. 
+            // 
+         }
+
+         cout << "250 " << getHostName() << CRLF;
+         state = "READY";
+      }