Add checks for broken QSettings

Ricodebug crashed for me on startup using

Linux 3.19.2
Python 3.4.3
PyQt4 4.11.3.

I could quick-fix it at jakobwinkler/ricodebug@92508c07700af55d0ea4caa20780ca11ec99262a but I'm unsure about this. If I understood the docs correctly, QSettings.value should never return None (logs below). Also I don't know if I followed any coding conventions because I'm not very familiar with python.

Traceback (most recent call last):
  File "ricodebug.py", line 79, in <module>
    main()
  File "ricodebug.py", line 66, in main
    window = MainWindow()
  File "/home/erpfi/tmp/ricodebug/src/views/mainwindow.py", line 67, in __init__
    self.recentFileHandler = RecentFileHandler(self, self.ui.menuRecentlyUsedFiles, self.do)
  File "/home/erpfi/tmp/ricodebug/src/helpers/recentfilehandler.py", line 65, in __init__
    self.__loadRecentFiles()
  File "/home/erpfi/tmp/ricodebug/src/helpers/recentfilehandler.py", line 114, in __loadRecentFiles
    if exists(filename):
  File "/usr/lib/python3.4/genericpath.py", line 19, in exists
    os.stat(path)
TypeError: stat: can't specify None for path argument
QObject::startTimer: QTimer can only be used with threads started with QThread
QObject::startTimer: QTimer can only be used with threads started with QThread
Segmentation fault (core dumped)

After fixing this I got:

Traceback (most recent call last):
  File "ricodebug.py", line 79, in <module>
    main()
  File "ricodebug.py", line 66, in main
    window = MainWindow()
  File "/home/erpfi/tmp/ricodebug/src/views/mainwindow.py", line 92, in __init__
    self.readSettings()
  File "/home/erpfi/tmp/ricodebug/src/views/mainwindow.py", line 271, in readSettings
    self.restoreGeometry(self.settings.value("geometry"))
TypeError: QWidget.restoreGeometry(QByteArray): argument 1 has unexpected type 'NoneType'
QObject::startTimer: QTimer can only be used with threads started with QThread
QObject::startTimer: QTimer can only be used with threads started with QThread
QObject::startTimer: QTimer can only be used with threads started with QThread
QObject::startTimer: QTimer can only be used with threads started with QThread
QObject::startTimer: QTimer can only be used with threads started with QThread
Segmentation fault (core dumped)

rainerf / ricodebug

Add checks for broken QSettings #52