GUIHelpers::Error::what() returned a char* to a temporary QByteArray which is invalid after leaving what()

The crash happens because of trying to create subdir "autosave" in the project directory, which is not existing anymore.

The fix
a) avoids creating the subdir, if the project dir is not existing
b) catches any exception in autosave, so autosave itself never causes a crash by an unhandled exception

used script:
    t = re.sub(r'new QString\(("[^"]*?")\)', r'###NEW(\1)', t)
    t = re.sub(r'QString\(("[^"]*?")\)(\s*\+\s*)', r'###ADD(\1)\2', t)
    t = re.sub(r'QString\(("[^"]*?")\)(\s*\.)', r'###ADD(\1)\2', t)
    t = re.sub(r'QString\(("[^"]*?")\)', r'\1', t)
    t = re.sub(r'###NEW\(("[^"]*?")\)', r'new QString(\1)', t)
    t = re.sub(r'###ADD\(("[^"]*?")\)', r'QString(\1)', t)

Signal/slot renaming between FitSuiteWidget and GUIFitObserver to better describe what is flying around.