Make sure to save config on crash

qutebrowser/app.py

@@ -157,6 +157,7 @@ class QuteBrowser(QApplication):
             argv = [sys.executable] + sys.argv + pages
             logging.debug('Running {} with args {}'.format(sys.executable,
                                                            argv))
+            config.config.save()
             sys.stdout.flush()
             # FIXME this seems broken on Windows, execv() splits on whitespace
             # in arguments?!?

qutebrowser/utils/config.py

@@ -187,6 +187,8 @@ class Config(ConfigParser):
         logging.debug("Saving config to {}".format(self.configfile))
         with open(self.configfile, 'w') as f:
             self.write(f)
+            f.flush()
+            os.fsync(f.fileno())
 
     def dump_userconfig(self):
         """Returns the part of the config which was changed by the user as a