Fixed #7614: the quickening has come, and there now is only one UploadedFile....

Fixed #7614: the quickening has come, and there now is only one UploadedFile. On top of that, UploadedFile's interface has been improved:

  * The API now more closely matches a proper file API. This unfortunately means a few backwards-incompatible renamings; see BackwardsIncompatibleChanges. This refs #7593.
  * While we were at it, renamed chunk() to chunks() to clarify that it's an iterator.
  * Temporary uploaded files now property use the tempfile library behind the scenes which should ensure better cleanup of tempfiles (refs #7593 again).

Thanks to Mike Axiak for the bulk of this patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7859 bcc190cf-cafb-0310-a4f2-bffc1f526a37