title: UnicodeError when try to send a file with greek filename
body: <p>I have created and populated Greek names in a set() and I then pass this set of values to a view function.</p>
  
  <p>When I try to print this set Greek names appear as jibberish. I believe this has somethign to do that Apache mod_wsgi or Bottle doens't start with utf-8 support.</p>
  
  <p>How can I tell Apache/Bottle to use LANG=el_GR.utf-8 so I can display unicode properly because I believe that's the case here?</p>
  
  <p>I looked for AddDefaultCharset utf-8 in httpd.conf but it is already enabled, so I have to ask why the Greek chars appear as jibberish?</p>
  
  <p>This is when i try to download a file with a greek filename.</p>
  
  <pre><code>Error: 500 Internal Server Error
  Sorry, the requested URL 'http://superhost.gr/downloads/file' caused an error:
  
  Internal Server Error
  Exception:
  UnicodeEncodeError('ascii', '/static/files/Î\x92Î¹Î¿Î³Ï\x81Î±Ï\x86Î¹ÎºÏ\x8c - Î\x9dÎ¯ÎºÎ¿Ï\x82.docx', 14, 34, 'ordinal not in range(128)')
  Traceback:
  Traceback (most recent call last):
    File "/usr/lib/python3.6/site-packages/bottle.py", line 862, in _handle
      return route.call(**args)
    File "/usr/lib/python3.6/site-packages/bottle.py", line 1740, in wrapper
      rv = callback(*a, **ka)
    File "/usr/lib/python3.6/site-packages/bottle.py", line 2690, in wrapper
      return func(*a, **ka)
    File "/home/nikos/public_html/downloads.py", line 148, in file
      return static_file(filename, root='/static/files', download=True)
    File "/usr/lib/python3.6/site-packages/bottle.py", line 2471, in static_file
      if not os.path.exists(filename) or not os.path.isfile(filename):
    File "/usr/lib64/python3.6/genericpath.py", line 19, in exists
      os.stat(path)
  UnicodeEncodeError: 'ascii' codec can't encode characters in position 14-33: ordinal not in range(128)
  </code></pre>
  
  <p>The code use to download the file is:</p>
  
  <pre><code>return static_file(filename, root='/static/files', download=True)
  </code></pre>
  
  <p>my system is et to utf-8</p>
  
  <pre><code>[root@superhost public_html]# echo $LANG
  en_US.UTF-8
  </code></pre>
  
  <p>Perhaps something with Apache or is it a probelm with Python3 ?</p>