Fix dash parser and more refactor

- Add new itags

stream/Stream.java

@@ -0,0 +1,39 @@
+package org.schabi.newpipe.extractor.stream;
+
+import java.io.Serializable;
+import java.util.List;
+
+public abstract class Stream implements Serializable {
+    public String url;
+    public int format = -1;
+
+    public Stream(String url, int format) {
+        this.url = url;
+        this.format = format;
+    }
+
+    /**
+     * Reveals whether two streams are the same, but have different urls
+     */
+    public boolean equalStats(Stream cmp) {
+        return cmp != null && format == cmp.format;
+    }
+
+    /**
+     * Reveals whether two Streams are equal
+     */
+    public boolean equals(Stream cmp) {
+        return equalStats(cmp) && url.equals(cmp.url);
+    }
+
+    /**
+     * Check if the list already contains one stream with equals stats
+     */
+    public static boolean containSimilarStream(Stream stream, List<? extends Stream> streamList) {
+        if (stream == null || streamList == null) return false;
+        for (Stream cmpStream : streamList) {
+            if (stream.equalStats(cmpStream)) return true;
+        }
+        return false;
+    }
+}