Fix checkstyle issues

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

@@ -8,10 +8,8 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.UnsupportedEncodingException;
 import java.net.MalformedURLException;
 import java.net.URL;
-import java.net.URLDecoder;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.HashMap;

src/main/java/de/tudresden/inf/mci/brailleplot/util/GeneralResource.java

@@ -9,7 +9,6 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
-import java.net.URLDecoder;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;