Change configuration saving

* Save initial configuration after all the plugins are done with
  their delayed initialization

* Save configuration when the autosave timer triggers. The disks
  are in use at that time anyway and saving can be turned off
  completely

* Save settings when closing the options page dialog

Change-Id: Idcf9ad61e8f9b94899c580d5a855a883a62f8dc0
Reviewed-by: Majid Khan <mkhan3189@gmail.com>
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/coreplugin/dialogs/settingsdialog.cpp

@@ -542,6 +542,8 @@ void SettingsDialog::done(int val)
     settings->setValue(QLatin1String(categoryKeyC), m_currentCategory);
     settings->setValue(QLatin1String(pageKeyC), m_currentPage);
 
+    ICore::saveSettings(); // save all settings
+
     // exit all additional event loops, see comment in execDialog()
     QListIterator<QEventLoop *> it(m_eventLoops);
     it.toBack();