* Downloader rewrite
- Rewrite downloader to use coroutines instead of a thread
- Remove unused Page functions
- Add page progress
- Add ProgressResponseBody
- Add support for canceling a download in the middle of downloading
- Fix clear download queue
* Minor fix
* Minor improvements
- notifyAllClients now launches in another thread and only sends new data every second
- Better handling of download queue checker in step()
- Minor improvements and fixes
* Reorder downloads
* Download in parallel by source
* Remove TODO
Mitchell Syer
2195c3df76