initReceiver can potentially use NULL pointer for rist_logging_settings

bool RISTNetReceiver::initReceiver(std::vector<std::string> &rURLList,
                                   RISTNetReceiver::RISTNetReceiverSettings &rSettings) {
    ...

    // Default log settings
    rist_logging_settings* lSettingsPtr = rSettings.mLogSetting.get();
    lStatus = rist_logging_set(&lSettingsPtr, rSettings.mLogLevel, nullptr, nullptr, nullptr, stderr);
    mLoggingScope.reset(lSettingsPtr);
    if (lStatus) {
        LOGGER(true, LOGG_ERROR, "rist_logging_set failed.")
        return false;
    }


    lStatus = rist_receiver_create(&mRistContext, rSettings.mProfile, rSettings.mLogSetting.get()); // --> Problem here
    if (lStatus) {
        LOGGER(true, LOGG_ERROR, "rist_receiver_create fail.")
        return false;
    }
...

If initReceiver is called with a freshly created RistNetReceiverSettings (like in the example in the README), rSettings.mLogSetting.get() will point to NULL.

This is not a problem when calling rist_logging_set(&lSettingsPtr...) because inside that function, the struct will be created if the pointer is NULL (rist/src/logging.c:211).

But when rist_receiver_create is called using rSettings.mLogSetting.get(), that still points to NULL and leads to a crash. A partial solution can be this (use lSettingsPtr because it was initialized in logging.c):

lStatus = rist_receiver_create(&mRistContext, rSettings.mProfile, lSettingsPtr);

But rSettings.mLogSetting keeps as a null pointer, so maybe there is a better solution.

This also happens for initSender().

EDIT: if anyone sees this, i fixed it in https://github.com/swxtchio/rist-cpp/pull/4/files