Deal with Internationalized Domain Name in URI

This fixes https://anki.tenderapp.com/discussions/ankidesktop/17132-anki-reports-an-error-when-pasting-an-image-from-non-ascii-url

The problem is that urllib2 can't work with IDN. However, it's perfectly valid
to have such URIs in HTML, and Firefox, when copying image, generates exactly
this kind of HTML.

aqt/editor.py

@@ -7,6 +7,8 @@ import urllib2
 import ctypes
 import urllib
 
+from urlparse import urlparse, urlunparse
+
 from anki.lang import _
 from aqt.qt import *
 from anki.utils import stripHTML, isWin, isMac, namedtmp, json, stripHTMLMedia
@@ -837,6 +839,12 @@ to a cloze type first, via Edit>Change Note Type."""))
         self.mw.progress.start(
             immediate=True, parent=self.parentWindow)
         try:
+            # urllib2 doesn't work properly with IRI
+            # The following code translates IRI to standard URI
+            scheme, netloc, path, params, query, fragment = urlparse(url)
+            idna_netloc = urllib2.unquote(netloc.encode("ascii")).decode("utf-8").encode("idna")
+            url = urlunparse([scheme, idna_netloc, path, params, query, fragment])
+
             req = urllib2.Request(url, None, {
                 'User-Agent': 'Mozilla/5.0 (compatible; Anki)'})
             filecontents = urllib2.urlopen(req).read()