message: enable screen sharing for ff 52 even without extension (fix
diff: @@ -248,8 +248,10 @@ jsxc.webrtc = {
  win.find('.jsxc_tools .jsxc_settings').after(div);
  var screenMediaExtension = jsxc.options.get('screenMediaExtension') || {};
  - var browser = self.conn.jingle.RTC.webrtcDetectedBrowser;
  - if (screenMediaExtension[browser] || jsxc.storage.getItem('debug')) {
  + var browserDetails = self.conn.jingle.RTC.browserDetails || {};
  + var browser = browserDetails.browser;
  + var version = browserDetails.version;
  + if (screenMediaExtension[browser] || jsxc.storage.getItem('debug') || (browser === 'firefox' && version >= 52)) {
  // Add screen sharing button if extension is available or we are in debug mode
  var a = $('<a>');
  a.text($.t('Share_screen'));
  