Merge pull request 'added support for !empty response' (#1) from kirillius-patch-1 into master

Reviewed-on: #1

pom.xml

@@ -9,7 +9,7 @@
   <modelVersion>4.0.0</modelVersion>  
   <groupId>me.legrange</groupId>  
   <artifactId>mikrotik</artifactId>  
-  <version>3.0.8</version>  
+  <version>3.0.8.1</version>  
   <packaging>jar</packaging>  
   <name>Mikrotik API Java Client Library</name>  
   <url>https://github.com/GideonLeGrange/mikrotik-java</url>  

src/main/java/me/legrange/mikrotik/impl/ApiConnectionImpl.java

@@ -306,6 +306,7 @@ public final class ApiConnectionImpl extends ApiConnection {
             switch (line) {
                 case "!re":
                     return unpackRe();
+                case "!empty":
                 case "!done":
                     return unpackDone();
                 case "!trap":