use input file/dir path as download path

closes #357

index.js

@@ -12,6 +12,7 @@ var parallel = require('run-parallel')
 var parseTorrent = require('parse-torrent')
 var speedometer = require('speedometer')
 var zeroFill = require('zero-fill')
+var path = require('path')
 
 var FSStorage = require('./lib/fs-storage') // browser exclude
 var Storage = require('./lib/storage')
@@ -208,6 +209,7 @@ WebTorrent.prototype.seed = function (input, opts, onseed) {
   if (!opts) opts = {}
   opts.noVerify = true
   opts.createdBy = 'WebTorrent/' + VERSION
+  opts.path = typeof input === 'string' ? path.dirname(input) : opts.path
 
   var streams
   var torrent = self.add(undefined, opts, function (torrent) {