Fix accessibility.

src/main/java/de/tudresden/inf/mci/brailleplot/configparser/ConfigurationParser.java

@@ -17,7 +17,7 @@ import java.util.Set;
  * @version 2019.07.18
  */
 
-abstract class ConfigurationParser {
+public abstract class ConfigurationParser {
 
     private FileInputStream mInput;
     private ConfigurationValidator mValidator;

src/main/java/de/tudresden/inf/mci/brailleplot/configparser/ValidProperty.java

@@ -5,7 +5,7 @@ package de.tudresden.inf.mci.brailleplot.configparser;
  * @author Leonard Kupper
  * @version 2019.06.04
  */
-abstract class ValidProperty {
+public abstract class ValidProperty {
     String mName;
     String mValue;