Remove unused imports

I searched for "StandardCharsets" to prevent possible bugs with Android KitKat. The import is unused and is therefor removed.
There are other usages of the StandardCharsets class in the test implementation, but those are not relevant.

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java

@@ -1,14 +1,6 @@
 package org.schabi.newpipe.extractor.services.youtube;
 
 import com.grack.nanojson.*;
-import com.grack.nanojson.JsonArray;
-import com.grack.nanojson.JsonObject;
-import com.grack.nanojson.JsonParser;
-import com.grack.nanojson.JsonParserException;
-import com.grack.nanojson.JsonWriter;
-
-import org.jsoup.Jsoup;
-import org.jsoup.nodes.Document;
 import org.schabi.newpipe.extractor.MetaInfo;
 import org.schabi.newpipe.extractor.Page;
 import org.schabi.newpipe.extractor.downloader.Response;
@@ -28,7 +20,6 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLDecoder;
-import java.nio.charset.StandardCharsets;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
@@ -38,10 +29,6 @@
 import static org.schabi.newpipe.extractor.NewPipe.getDownloader;
 import static org.schabi.newpipe.extractor.utils.JsonUtils.EMPTY_STRING;
 import static org.schabi.newpipe.extractor.utils.Utils.*;
-import static org.schabi.newpipe.extractor.utils.Utils.HTTP;
-import static org.schabi.newpipe.extractor.utils.Utils.HTTPS;
-import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
-import static org.schabi.newpipe.extractor.utils.Utils.join;
 
 /*
  * Created by Christian Schabesberger on 02.03.16.