Re: Set filenames in iget

[Chris Warburton]

Made the following iget changes:

 - Use basename on the last argument, to guess a filename
 - Capture stdout of get_iplayer and extract the saved filename from the
   last line, and check it exists as a file
 - Move the saved file to the guessed filename

A couple of other additions:

 - Give the user a 5 second countdown, to abort if the guessed filename
   is catastrophic (e.g. an empty string)
 - get_iplayer checks if it's connected to a tty; if not, it doesn't
   show progress info. By capturing stdout, we're failing this check, so
   we include a workaround to fake a tty and hence get output info