Minor changes to the UI and fixes to empty corpus queries

Change-Id: If9dce8fd2cdfe441a6637d6caaaa334e6921d420
diff --git a/plugin/src/main/java/de/ids_mannheim/korap/plkexport/PluginServer.java b/plugin/src/main/java/de/ids_mannheim/korap/plkexport/PluginServer.java
index 8bbd366..d51c2e7 100644
--- a/plugin/src/main/java/de/ids_mannheim/korap/plkexport/PluginServer.java
+++ b/plugin/src/main/java/de/ids_mannheim/korap/plkexport/PluginServer.java
@@ -60,7 +60,7 @@
                 properties.getProperty("api.scheme") +
                 "://" +
                 properties.getProperty("api.host") +
-                properties.getProperty("api.path") + ":" +
+                properties.getProperty("api.path","") + ":" +
                 properties.getProperty("api.port")
                 );
             jettyServer.join();