MP4 muxer +misc modifications

* allow retry downloads with "post-processing failed" error in the new muxer
* MPEG-4 muxer  ¡¡ no DASH output!!
* keep the progress if download fails
* remove TODO in SecondaryStreamHelper.java
* misc clean-up
* delete TestAlgo.java
* delete ExtSDDownloadFailedActivity.java and remove it from AndroidManifest.xml
* use hardcored version for changing icon colors

app/src/main/java/us/shandian/giga/postprocessing/TtmlConverter.java

@@ -0,0 +1,75 @@
+package us.shandian.giga.postprocessing;
+
+import android.util.Log;
+
+import org.schabi.newpipe.streams.io.SharpStream;
+import org.schabi.newpipe.streams.SubtitleConverter;
+import org.xml.sax.SAXException;
+
+import java.io.IOException;
+import java.text.ParseException;
+
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.xpath.XPathExpressionException;
+
+import us.shandian.giga.get.DownloadMission;
+import us.shandian.giga.postprocessing.io.SharpInputStream;
+
+/**
+ * @author kapodamy
+ */
+class TtmlConverter extends Postprocessing {
+    private static final String TAG = "TtmlConverter";
+
+    TtmlConverter(DownloadMission mission) {
+        // due how XmlPullParser works, the xml is fully loaded on the ram
+        super(mission, 0, true);
+    }
+
+    @Override
+    int process(SharpStream out, SharpStream... sources) throws IOException {
+        // check if the subtitle is already in srt and copy, this should never happen
+        String format = getArgumentAt(0, null);
+
+        if (format == null || format.equals("ttml")) {
+            SubtitleConverter ttmlDumper = new SubtitleConverter();
+
+            try {
+                ttmlDumper.dumpTTML(
+                        sources[0],
+                        out,
+                        getArgumentAt(1, "true").equals("true"),
+                        getArgumentAt(2, "true").equals("true")
+                );
+            } catch (Exception err) {
+                Log.e(TAG, "subtitle parse failed", err);
+
+                if (err instanceof IOException) {
+                    return 1;
+                } else if (err instanceof ParseException) {
+                    return 2;
+                } else if (err instanceof SAXException) {
+                    return 3;
+                } else if (err instanceof ParserConfigurationException) {
+                    return 4;
+                } else if (err instanceof XPathExpressionException) {
+                    return 7;
+                }
+
+                return 8;
+            }
+
+            return OK_RESULT;
+        } else if (format.equals("srt")) {
+            byte[] buffer = new byte[8 * 1024];
+            int read;
+            while ((read = sources[0].read(buffer)) > 0) {
+                out.write(buffer, 0, read);
+            }
+            return OK_RESULT;
+        }
+
+        throw new UnsupportedOperationException("Can't convert this subtitle, unimplemented format: " + format);
+    }
+
+}