Add tinylog logging

Change-Id: I530b4e7e3119444070cff2a25cc1450d33d8f563
diff --git a/src/main/java/de/ids_mannheim/korap/plkexport/ExWSConf.java b/src/main/java/de/ids_mannheim/korap/plkexport/ExWSConf.java
index 8382254..8313810 100644
--- a/src/main/java/de/ids_mannheim/korap/plkexport/ExWSConf.java
+++ b/src/main/java/de/ids_mannheim/korap/plkexport/ExWSConf.java
@@ -13,6 +13,8 @@
 import java.util.Properties;
 import java.nio.charset.StandardCharsets;
 
+import org.tinylog.Logger;
+
 public class ExWSConf {
 
     // Version of Export Plugin
@@ -48,7 +50,7 @@
                     .getResourceAsStream(propFile);
 
                 if (iFile == null) {
-                    System.err.println("Unable to load properties.");
+                    Logger.error("Unable to load properties.");
                     return null;
                 };
 
@@ -57,7 +59,7 @@
                 iFile.close();
             }
             catch (IOException e) {
-                System.err.println(e.getLocalizedMessage());
+                Logger.error(e);
                 return null;
             };
         };