Fixes #333 and fixes #334

Reproducing code:

```ruby
yu = a.get 'http://www.youtube.com/upload_classic'
@form = yu.forms.last

path = ARGV[0]
Dir.glob("#{path}*.{mp4,flv,mpg,mpeg}") { |fname|
  @form.file_upload.file_name = fname
  @form.submit
  }
```