* re-write download segmenting logic (issue #).
* clean-up download threads handling.
* fix race-condition if "pause" option in download context menu was selected, in the transition from "pending" to "finished" state.
* implement socket timeout error
* use 128k buffer size for copy
* use NewPipe HTTP user agent in the downloads
* automatically recover downloads with network errors that are queued
* full support for Directory API (Android Lollipop or later)
* best effort to handle any kind errors (missing file, revoked permissions, etc) and recover the download
* implemented directory choosing
* fix download database version upgrading
* misc. cleanup
* do not release permission on the old save path (if the user change the download directory) under SAF api
* re-work finished mission database
* re-work DownloadMission and bump it Serializable version
* keep the classic Java IO API
* SAF Tree API support on Android Lollipop or higher
* add wrapper for SAF stream opening
* implement Closeable in SharpStream to replace the dispose() method
* do required changes for this API:
** remove any file creation logic from DownloadInitializer
** make PostProcessing Serializable and reduce the number of iterations
** update all strings.xml files
** storage helpers: StoredDirectoryHelper & StoredFileHelper
** best effort to handle any kind of SAF errors/exceptions
* fast download pausing
* fix UI thread blocking when calling pause()
* check running threads before start the download
* fix null pointer exception in onDestroy in the download service, without calling onCreate method (android 8)
* fix content length reading
* use float overflow. Expensive, double is used instead
* fix invalid cast after click the mission body
* use a list for maximum attemps (downloads)
* minor clean up (DownloadManager.java)
* dont pass SharedPreferences instace to DownloadManager
* use a switch instead of checkbox for cross_network_downloads
* notify media scanner after deleting a finished download
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)
This improves downloading performance dramatically when cpu bound:
Before, even a high-end cpu from 2013 can't download faster than around 1MB/s.
The bigger read buffer size removes the need for a dedicated BufferedInputStream.
* Fix permission at some places
* Fix access problem for downloaded files with external player
* Store finished Downloads
* Remove binding to DownloadService just to download a file
* Javadoc
* Code improvements
