Add $savepath argument to $transmission->add() function

If $savepath argument is specified, the torrent will be downloaded to the value of $savepath
Add $savepath argument to $transmission->add() function

If $savepath argument is specified, the torrent will be downloaded to the value of $savepath.

Usage example:

$savepath = '/home/downloads/';
$torrent = $transmission->add(/* base64-encoded metainfo */, true,$savepath);
Merge pull request #28 from firesalp/patch-2