aria2/TODO

* Add HTTP POST support
* Add expires handling for Cookie
* Add SSL server cert verification
* Add SSL client cert support
* Better HTTP status handling
* Download files listed in a specifed file.
* Add the feature which adds or removes URLs on-the-fly.
* Add port range command-line option
* Add max peers command-line option
* Refacturing HttpConnection and FtpConnection
* Query resource by location
* List available os, version, etc for metalink
* ipv6(RFC2428 for ftp)
* Add silent mode.
* Save URLs and command-line arguments to .aria2 file.
* Add a control port for GUI frontend
* Add a version header to .aria2 file to check the compatibiliy.
* Use SharedHandle where it is useful.
* Rewrite Util::countBit
* Add Turkish translation.
* Add the message like "you can resume the transfer by invoking aria2 again" when the download stops.
* Add --bt-timeout command line option.
* Fix DefaultBtProgressInfoFile.cc: save(), load()
* Add a feature that if any existing file is detected, then
do not start downloading and print some useful message to the user.
* Fix Segfaults in BitfieldMan.cc:71
https://sourceforge.net/tracker/index.php?func=detail&aid=1606060&group_id=159897&atid=813673
* int32_t
* remove blockIndex