main commit

Post-processing infrastructure
* remove interfaces with one implementation
* fix download resources with unknow length
* marquee style for ProgressDrawable
* "view details" option in mission context menu
* notification for finished downloads
* postprocessing infrastructure: sub-missions, circular file, layers for layers of abstractions for Java IO streams
* Mp4 muxing (only DASH brand)
* WebM muxing
* Captions downloading
* alert dialog for overwrite existing downloads finished or not.

Misc changes
* delete SQLiteDownloadDataSource.java
* delete DownloadMissionSQLiteHelper.java
* implement Localization from #114

Misc fixes (this branch)
* restore old mission listeners variables. Prevents registered listeners get de-referenced on low-end devices
* DownloadManagerService.checkForRunningMission() now return false if the mission has a error.
* use Intent.FLAG_ACTIVITY_NEW_TASK when launching an activity from gigaget threads (apparently it is required in old versions of android)

More changes
* proper error handling "infrastructure"
* queue instead of multiple downloads
* move serialized pending downloads (.giga files) to app data
* stop downloads when swicthing to mobile network (never works, see 2nd point)
* save the thread count for next downloads
* a lot of incoherences fixed
* delete DownloadManagerTest.java (too many changes to keep this file updated)

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

@@ -0,0 +1,44 @@
+package us.shandian.giga.postprocessing;
+
+import org.schabi.newpipe.extractor.utils.WebMReader.TrackKind;
+import org.schabi.newpipe.extractor.utils.WebMReader.WebMTrack;
+import org.schabi.newpipe.extractor.utils.WebMWriter;
+import org.schabi.newpipe.extractor.utils.io.SharpStream;
+
+import java.io.IOException;
+
+import us.shandian.giga.get.DownloadMission;
+
+/**
+ * @author kapodamy
+ */
+class WebMMuxer extends Postprocessing {
+
+    WebMMuxer(DownloadMission mission) {
+        super(mission);
+        recommendedReserve = (1024 + 512) * 1024;// 1.50 MiB
+        worksOnSameFile = true;
+    }
+
+    @Override
+    int process(SharpStream out, SharpStream... sources) throws IOException {
+        WebMWriter muxer = new WebMWriter(sources);
+        muxer.parseSources();
+
+        // youtube uses a webm with a fake video track that acts as a "cover image"
+        WebMTrack[] tracks = muxer.getTracksFromSource(1);
+        int audioTrackIndex = 0;
+        for (int i = 0; i < tracks.length; i++) {
+            if (tracks[i].kind == TrackKind.Audio) {
+                audioTrackIndex = i;
+                break;
+            }
+        }
+
+        muxer.selectTracks(0, audioTrackIndex);
+        muxer.build(out);
+
+        return OK_RESULT;
+    }
+
+}