tujikawa - 2010-04-08

Implemented in r2039
From ChangeLog:
Added --save-session=FILE option. This option saves
error/unfinished downloads to FILE on exit. You can pass this
output file to aria2c with -i option on restart. Please note that
downloads added by aria2.addTorrent and aria2.addMetalink XML-RPC
method are not saved.