ProxyWebView segfaults on application exit.

[itziakos]

The following testcase demonstrates the issue. The test will segfault on windows 10 pyside 1.2.2 and python 2.7.13

import unittest
import faulthandler

from jigna.qt import QtCore, QtGui
from jigna.core.proxy_qwebview import ProxyQWebView

faulthandler.enable()

class TestProxyQWebview(unittest.TestCase):

    def setUp(self):
        self.app = QtGui.QApplication.instance() or QtGui.QApplication([])

    def test_setUrl(self):
        app = self.app

        def create():
            widget = ProxyQWebView()
            widget.show()
            widget.setUrl(QtCore.QUrl('https://www.enthought.com'))
            print 'DONE'

        QtCore.QTimer.singleShot(10, create)
        QtCore.QTimer.singleShot(10000, app.quit)
        print 'Start'
        app.exec_()